If the ISOGG designations were still useful, your idea about wildcard matching would be great. But unfortunately, they have some serious issues - they're essentially deprecated now, and that lettering system cannot handle early insertions in a feasible manner, and they are significantly behind FTDNA and YFull in branches and SNP's. The YFull tree appears to be based on the ISOGG tree, but has left it behind, and has switched to labeling branches by a primary SNP. So has FTDNA, and they are even farther ahead in naming SNP's and branches. So if you test at FTDNA, you will almost certainly receive a 'terminal' SNP that YFull doesn't yet have, and well beyond what ISOGG has.
I prefer something I like to call a 'haplotrail', the trail of SNP's from the ancients to your current haplogroup. It let's anyone compare trails, no matter where they have tested or how far they have tested. And the listed SNP's become searchable this way. For much more on this problem, see my comments here, plus the subsequent comments.