to be honest, i feel that kajiura-sama also needs a break. i love her songs, dont get me wrong, but i just feel that its getting to be a little more towards the reuse-recycle system. then again, kajiura-sama on a break =/= kalafina on a break.
MAIN PROBLEM is with kalafina's management. the problem doesnt lie with the three ladies themselves. i wont know for certain, but i can guess that the girls do NOT have much say for the events/activities lineup. what they have, is probably a free rein to do what they want FOR/DURING the event. therefore, they have to work with what they have, and it appears to be too much.
sure, the ladies are old enough to decide for themselves just when enough is enough, and request for a break. but what if, the management are the ones who have an iron grip on who gets breaks, who doesnt, and how long a break?
plus like i said, if its about wakana, i doubt she finds her participation in two groups to be taxing on her. a few times i wonder if wakana is actually trying too hard thus resulting in some less than perfect performances.
Wakana does have to rest if she wants to save her voice. But the problem is that it's pretty much impossible with her schedule and I doubt their management will allow them to have a half a year break, because at that time they won't bring any money 
So I would definitely not call it representative of her performing skills.