WM is always at risk of bombing, current roster or not. then again, so is every show that is done by any company in the world. that's the risk of programming. however, aside from that obvious point, the OP does have a valid argument. lots of names have been retired or injured for the majority of this year: HBK, Taker, Batista, Y2J, Triple H, Punk, even Orton and Rey have been for a time and worked lighter schedules or lots of tag matches, etc. and i'd like to think Christian, but many would argue that he's not a big name. that's a matter of opinion i guess.
still, this WM could potentially be the second worst in the history. WM 9 deserves top honors. this could be close. lots of injuries and retirements are still pending and the current roster is uncertain at best. and then again, this could be the greatest WM in the history, if booked properly. that's the tough part, obviously.
here's my thought for a possible card that i'd like to see and reasons why and how i think this could work. the matches are in no particular order other than the order in which i think of them.
1. Kane vs. Sheamus. there just needs to be a good monster match and these two could do it. i don't want to see Sheamus not on the card and i don't want to see his feud with Triple H reignite here. maybe Triple H returns and wins his match at Mania and Sheamus wins his so that they both have momentum when their feud does reignite after Mania. that could be a possibility. i'm not sure how you'd have Sheamus and Kane meet up though. maybe just for Brand Supremacy or something like that. except, you know, rather than having a trophy that means nothing (Bragging Rights, anyone?) the winner could get a draft pick or something. so now you have a monster match with two solid workers and former world champs in a match that has a reason and a reward. that's a start.
2. Tag Titles. these freaking things have to be defended on PPV and the biggest PPV of the year FOR FREAKING SURE! it's the only way to rebuild the division. make it important enough to show on tv and even make it important enough for people to pay to see it on tv. and you need some actual teams. Miz & Morrison would be great, but i'm enjoying their respective singles runs and pairing them up would ruin their current pushes. so scratch them. Edge & Christian is a dark horse team that i'd love to see return here to win the belts if only so they could help rebuild the division, later split (maybe around Survivor Series) and feud at the following Mania. but realistically, how about just letting the Uso's fight against Ted Dibiase and his Fortunate Sons stable? that would mean that brother Bret would have to return from injury and this stable created, but there's plenty of time to do that. in fact, have the Uso's and Fortunate Sons and Hart Dynasty (don't split this team up! have Bret Hart return to mend the fences because these guys may not make it as singles stars and the WWE needs more actual tag teams!) and make it a triple threat tag match. maybe even have some legends accompany each team: Bret Hart and Hart Dynasty vs. Million Dollar Man Ted Dibiase and Fortunate Sons vs. Rikishi and Uso's. that's my tag titles match for WM.
3. Miz vs. Morrison. no title here. but a #1 Contender's spot for the title. let Miz and Morrison feud a few weeks or month or two prior. plus they already have history. Miz can lose the title and Morrison can lose his #1 spot and so these two can feud for that spot. this also gives us a preview of how an audience would respond to these two in a main event fighting for the actual title itself. get some young blood in Mania in matches that matter. this would be one of them.
4. Punk vs. Bryan, US Title. just make this happen. no questions asked. maybe make it a 30-minute Iron Man Match. i'd say make it a 30-minute Iron Match (a la Angle and Benoit from years past) but i'm not sure how Punk would do in Submissions only. forgive my ignorance, but i'm not too familiar with Punk in ROH. but these two could put on a clinic, whether submissions only or a regular Iron Match rules for 30 minutes and chew up some of the clock if people are worried about paying money for 2 hours worth of card. plus, c'mon... who doesn't want to see this match? they've already been teasing the feud. Punk should be healed by then.
5. Taker vs. Barrett. this gets Taker in a match with a young guy. hopefully, this would mean that Barrett could improve as he'd be learning with a major vet and legend, plus the storyline makes sense as Nexus buried Taker.
6. MITB. let Kofi win this thing this year. he needs to have his push reinstalled. put Swagger, MVP, Kaval (keep him on tv and not look so weak!), Bourne, and Rhodes in this match. 6 is a better number than 10. it's just too cluttered otherwise.
7. Orton vs. Edge, WHC. have these guys actually finish their feud from last year. it just kinda stopped because of Orton's shoulder injury. so let these guys feud as they have tons of history and can make this work. plus, it hasn't been done at Mania before.
8. IC Title. also needs to be defended on tv if it's to be taken seriously. so i say have Ziggler go against a returning Jericho. no matter who gets the title, the real winner here is the audience. Jericho can either win and put on great feuds and matches with anybody, or he can lose and put Ziggler even more over than he already is.
9. Big Show vs. any celebrity. maybe even one last Brock Lesnar fight. these two had some pretty incredible matches and moments. not clinics, but still impressive stuff to watch. especially the ring collapsing. but really. any celebrity would do. that's kind of Big Show's Mania thing.
10. Del Rio vs. Cena for the WWE title. hear me out on this one. a guaranteed draw in Cena. Del Rio is a young up and coming heel. this could be as simple as having Del Rio win the Rumble or as silly as Del Rio being insulted by the Juan Cena gimmick. or maybe have Cena stand up and defend his friends that are being injured in Christian and Rey. i'm not sure how to write this up perfectly, but even letting Del Rio win the Rumble wouldn't be too impossible to believe. this guy is on a major push and tear and so have him go against the top guy in the company. plus, it's never been seen, so people might actually be interested in seeing it happen. i know he's no Eddie Guerrero (at least, not now he's not... time will only tell) but you could make it a street fight or something and tie it in to the history that Cena and Guerrero had.
11. Christian vs. Rey. simple here. have Christian go heel on Rey. Christian needs something fresh and he could turn on Rey because he got his first injury when trying to defend Rey against Del Rio. this gets them both on PPV and they could have a good match. plus, it freshens up Christian's character and allows him to fight for some titles against face champions.
12. Triple H. quite honestly, i'm not sure how to book him. he's returning. and it'd be highly unlikely, for multiple reasons, that he would not be at WM in some way. so maybe have him go against anyone... or referee if he's still hurting some. maybe go against Zeke. maybe even have Zeke go over to build up some credibility with him. or maybe go crazy and have him go against Regal or Goldust or another legend just to put on a good match with some good ring psychology so that the younger guys can just watch and learn. but get Triple H on the card, either against Zeke or one of the aforementioned two legends for whichever reason chosen. either to elevate Zeke and make him a credible guy or to demonstrate some older-school ring psychology to the younger guys.
so that'd be how i'd do the card and quite frankly, it'd be the first WM that i'd be seriously excited to watch because it'd have matches that haven't been seen before or often, all the titles defended (except the divas, because nobody really cares) and because there would be reasons for the matches (draft picks, titles, contenderships, returns from injury, etc) and feuds.
so the world's longest answer to a very short and easy question: is Mania in danger of bombing with the current roster? the answer is yes. but then again, it could also be the greatest Mania ever. it just all depends on how it's written.