As you can tell from the last few days' activities on these forums, T10 is a sticky issue

Some bought 4T10 and like it, some don't. Some never bought 4T10 or even 2T10 and judged it on its text alone (I'm one of these). Opinions will differ and it depends on a lot of things.
Personally, I run 10s and only get to occasionally PUG 25s, so the likelihood of getting a token to upgrade i251 T10 is not great and not something I'll rely on. So upgrading from i245 pieces to i251 wasn't a great choice for my emblems, and it particularly wasn't ideal when I was trading off crit/haste pieces for crit/spirit or haste/spirit, especially if they weren't going to get to i264 any time soon. If you think 4T10 would be upgraded to i264 soon, then they're probably not a bad choice. That's not the case for me though, so I'm doing what I can with offset and ICC drops.
Currently, IMHO, 2T10 is very forgettable and 4T10 is interesting, and I'd pick it up eventually to play with it and maybe try some hard modes. If this change goes through though, 4T10 isn't something I'll pursue except for its possibility to upgrade to i264, with the bonus being a very unimpressive plus.