Well, Paul Heyman frequently reminding us of what happened, how historic it was and that he played some role in it is a way of keeping Brock Lesnar in people's thoughts until he makes his return to television. It's possible that it's also used as a way of hinting that there's a POSSIBLE rematch between the two somewhere down the road. It's also possible that it's something that's being used as a means of continuing to put heat on Heyman & Lesnar, which is working as even a lot of hardcore smarks no longer pop for Heyman as they once did.
The problem with a rematch against Taker is that we're not all that likely to get a great match out of them. It was obvious to anyone who watched that Taker was in pretty rough shape at WrestleMania XXX. He wasn't in great cardio shape and he was softer/flabbier than I can ever recall, though it's understandable if the various aches & pains he endures keeps him from working out the way he once did. At 49 years old, Taker's someone who still has a lot of years left in the grand game of life and while there are some wrestlers who age like a fine wine, there's a distinct possibility that Taker won't be one of them.
I give Taker credit for genuinely trying at WrestleMania XXX. He obviously wasn't in the best shape and there were reports that came out after 'Mania suggesting that he may have somehow injured himself a few days prior to the event somehow. All in all, the match just wasn't that great, but it was extraordinarily memorable. Taker losing, which was unthinkable, is the only thing that saved the match from being a disaster. To top it all off, Taker was injured during the match. It was serious enough that Taker allowed himself to be taken away from the arena in an ambulance and it was serious enough that Vince himself got into the ambulance with him. Several years back, Taker was caught up in the pyro on stage at Elimination Chamber and suffered some pretty painful burns as a result, but went ahead with the match anyway, so for him to be willing to get in an ambulance suggests that he was really in rough shape after his match with Lesnar. About a month after WM, Michelle McCool put a message on Twitter asking people for their prayers as Taker wasn't doing all that well, so Taker was feeling the effects of his match against Lesnar a full month after it happened.
Personally, I think it's time for Taker to hang it up. I'd hate for his legacy to be tarnished by getting in there to wrestle knowing that he's not able to deliver the way he once did. Allegedly, Taker said he'd walk away if it ever got to that and I think that's what it's getting to. I'd love to see him come back just so he could be given a proper send off that he deserves and while he didn't get completely mangled in his match with Lesnar as badly as I thought he would, everybody's biggest concern took place in that he was hurt badly enough to be hospitalized.