It'd depend on various factors. Sometimes, different promoters had idea as to what a wrestler was supposed to be; Vince isn't nor wasn't the only guy who looked at someone, saw what they brought to the ring, saw their personality, etc. and decided based on that whether or not a guy could get over in his neck of the woods.
Using the Young Bucks as examples, I don't think they'd have really been given an opportunity in a lot of the more southern based territories like Memphis, Georgia, Florida & the Mid-Atlantic territories really put more emphasis on the "rasslin" style. Guys today who do a lot of flips, flops, heavily choreographed spots, didn't sell enough, etc. really wouldn't have been viewed as real wrestlers by many of the promoters nor a lot of the other wrestlers in the territories themselves. If you're someone that's more of the ground & pound type, someone who could brawl or someone who had great technical ability, then I think your odds go up considerably. I could see the Brisoes being welcome in places like Texas, Memphis, Georgia, Florida, Mid-Atlantic, NWA Tri-State/Mid-South/UWF, Smoky Mountain, etc.
After ECW became the ECW everyone is familiar with, all you really had to be willing to do was to go out there and essentially risk life & limb for gas money. I'm not saying there weren't good wrestlers in ECW, but being a good wrestler wasn't necessarily a requirement as they didn't have the highest of standards; you just had to be willing to risk your ass in matches that were extremely stiff, featured dangerous spots or a combination of both.
Wrestlers during the territory days, let's say circa 1965 to 1985 in the United States, who were under 6'0" and/or less than 200 lbs. would have had a difficult time because more emphasis was placed on the "heavyweight" aspect of things. During those days, guys who were 225 lbs. were considered small, so I think it'd been a hard time for wrestlers who you could visibly tell were much lighter. It can be hard sometimes to tell how tall a wrestler is or how much they weigh just based on perception, but there are also times it's pretty obvious. For instance, Neville looks like he could easily pass for 220 lbs. but it's also obvious that he's only about 5'7" or so and that would hinder him. As a result, smaller statured wrestlers of today would've been better off going to EMLL, CMLL of today, or the UWA in Mexico and the WWC of the Caribbean. Even in that mid 60s to mid 80s time period, Japan was still more focused on "heavyweight" titles and wrestlers.
