Whatever happened to the concept of "You want a specific bonus, you go out of your way to get/earn it"? This really isn't any different from saying:
"It's not fair that some people have played more PvP but less PvE than me have full War Hero sets:
1: Make it so that War hero gear is purchasable with just credits.
2: Make it so that War hero gear isn't better than other stuff so that time invested doesn't equate to a bonus."
That's pretty much what you're saying, except with a different subject. There's nothing stopping you from going out and getting these buffs for yourself, it didn't have it's availability limited to a specific time frame.
Secondly, at some point, I imagine they will be purchasable with credits. I recall Bioware saying that some things were going to start off as legacy only unlocks and then transition into credit unlocks in the future.
If you're not content to wait for when/if that happens, then you have to ask yourself how much the buffs mean to you. If they are that massive a difference to your viability, as an avid PvP'er you'll gladly go out and acquire the buffs. If they're not that massive that they warrant you putting effort in, then it's probably also not worth complaining about.
As a side note: Most dedicated PvPers that I know have rolled multiple classes, and that was before the buff sharing came into effect. They do it because a good PvP player knows the other class almost as well as their own, which is a level of understanding you can only genuinely get by playing it yourself.
You beat me to it! Damn you!