Meh. At least it's pretty unnoticeable.
It would be better if either:
A) There was some indicator of how many championships that team had won. I'm not just saying this out of Celtic pride, either, just in general it seems kind of pointless to invoke past glory in such a vague way. Though this has the problem of cluttering the uniform, so I think I prefer ...
B) It was only the defending champs. Yeah, it would be kind of weird for players that leave their championship team the next season (LeBron), at least it would be a temporary, transitory thing. It would be kind of cool, actually, if they did it this way.
But, yeah, not a big fan. At least they it isn't too obvious and conspicuous, though. I'll probably forget all about it and not notice it again until halfway through the season.