It is though, you are trying to sell me on Bryan Vs Triple H instead of 2 guys who can gave great matches. Brock cant bring H to a great match when they work the same style so what makes you think Bryan could? Triple H just cant have good matches anymore.
It's fine that you prefer Bryan/Sheamus over Bryan/Triple H but being objective about the whole thing, it isn't just about having a 'great match' with someone. As was said, Bryan can have great matches with pretty much anyone. Hell, he could have an amazing match with Tyson Kidd, but that doesn't mean one should automatically prefer that match over a match with a bigger star like HHH. Great matches can happen at anytime (even on Raw), but Wrestlemania is your chance to become "immortal", as the old cliche goes, and what has the bigger chance of being remembered as a huge moment for decades to come? Bryan defeating Sheamus or Bryan defeating Triple H? (That's a rhetorical question, btw.) Bryan facing (and defeating) HHH makes a world of more sense from a storytelling POV than Bryan defeating Sheamus.
It should also be kept in mind that when there's a great enough backstory to a match, then the actual match itself becomes 100x better just because the amazing story you've crafted has made people really want to see two guys finally get in the ring and get their hands on each other. After everything HHH has put Bryan through and after who-knows-what they'll do during the actual build to Mania (I could see Bryan causing HHH to lose it and bring out the sledgehammer in an attempt to hurt him or something), then it should be exciting enough just to see Bryan finally get to lay his hands on HHH in the ring and vice versa. That aspect alone and the aftermath of it (HHH having to look everyone in the eye after suffering a loss at the hands of Bryan) is enough to sell most people on the match, I'd figure.
(I also disagree anyway with HHH's matches with Brock and Undertaker being mediocre.)