You're assuming they'll implement +power/+prec/etc as account bonus but there's no indication they will do that as that would create unfair advantages in PvP. Right now it looks like MF/GF/Karma gain and XP gain only, so basically a type of permanent pots. It's actually quite clever in a way: the longer you play while getting achievement points the easier it will get to gain loot/gold/karma/xp.
I am perfectly aware that all these bonuses grant is more gold/xp/karma/.. and not power.
The problem is that there's absolutely no reason to not want these stats: they make your characters better. For instance, when talking about vanity items, they make you prettier and guy with the prettiest armour is doesn't get any extra game bonuses. So if you don't like said pretty, there's no reason to not get it.
But as I said, there's no reason to not want these bonuses because having them makes your characters better at no downside.
Do we really need more features that reward players for wasting tons of their time on the game? Especially if these rewards have a game-affecting result and if we are getting said rewards instead of vanity ones.
(Now, obviously, I do not plan on grinding these things, because I consider the amount of time needed to grind them to be a complete waste: but this now means my characters haven't plateaued. Of course, the fact that my characters now aren't even reaching the power plateau (result of ascended (and the aforementioned lvl 80 grind)/WvW grind) is more distressing than the fact that I am getting less gold, but this certainly isn't helping. It puts GW2 into a different category of games: games where grinders are supposed to get the best results and honestly, there are much better games out there that give grinders this feeling. And now GW2 is competing with those games and that's why we are seeing power seeing power creep in balancing and we are seeing the above mentioned stats creep. Come on, we've already been down this road and it certainly didn't end peachy for GW1. Why make the same dumb-ass mistakes all over again, A.Net?)