When it comes down to it, there's only two real issues that Celtavian has highlighted, neither of which are wrong for what was experienced... but also neither of which require something "to be done" on WotC's part.
A lot of dragon encounters made Celtavian feel the best course of action for their group was for him to use his one concentration spell to buff the fighter, and thus he was stuck not having the capability of using any other buffs. Okay. Sound reasoning, sound strategy for the situation they found themselves in. That really isn't debatable. Yeah, there were possibly other things that could have happened up until that point that might have mitigated the situation, but since the party just never found themselves that opportunity, it was what it was.
The second issue though is whether this makes the concentration mechanic a problem to the point where WotC needs to do something about it. That's where I think the real disagreements are coming from in the thread-- people seem to be reacting to Celtavian's problem as though he thinks that what occurred in his campaign is a real problem that has to be "fixed" by the designers, as opposed to just individual tables making their own house rules to lessen the issue if they feel like it's necessary (like KarinsDad has done). People are addressing his game as though to suggest that his was an outlier situation and thus can't be used as "proof" that the mechanic is bad, and that it doesn't warrant WotC producing errata to change the mechanic officially.
But here's the thing... I don't think Celtavian is commenting on all of this in an effort to actually get the rule changed officially in errata. I think he's just pointing out what happened in his game and how the concentration mechanic is not a foolproof rule and does have issues. Thus allowing everyone to just think about it and have to decide whether something might eventually be done in their own game. So there's no real point in anyone arguing with Celtavian about how what he did might have been "wrong" or "not necessary"... because 1) the game's already over so nothing can be changed... and 2) he's not using his experience as proof to call for official changes in the rules, so what does it matter if what happened to him won't happen to a lot of other tables?
Just take Celtavian's situation for what it is... a place where the concentration mechanic does potentially run up against a wall, and then keep your eyes open in your own game so that you don't suffer the same fate.