Thomas over the course of a season is a great offensive player, but his size becomes a real problem in the playoffs, even offensively where he has had a precipitous drop in effectiveness during the playoffs. When you couple that precipitous drop offensively with his already poor defense and he almost becomes a liability in the playoffs. The only thing he has done well in the playoffs is get to the line.
First of all, we're talking about a 10 game sample here, so those playoff performances probably need to be taken with a grain of salt.
Also, I believe in both of those series, Isaiah was (a) dealing with an injury of some kind and (b) playing without much help on offense.
Even setting aside those issues, offensive players becoming less efficient / effective in the playoffs is hardly limited to IT.
Kyle Lowry, for example, struggled quite a bit in the playoffs last season, and in previous seasons.
Toronto fans aren't clamoring to move on from Kyle Lowry, are they?
Bottom line here, my aim is not to make Isaiah out to be a flawless player. By no means. But I think a lot of the time people have a much easier time seeing his flaws as a player because of his size. And they tend to articulate their concerns about those flaws in a way that implies he could be easily replaced.
IT could not be easily replaced. Let's be really clear about that. I have some concerns about his longevity, and his ability to produce at the same level in the playoffs.
But what are our alternatives?
Surely the Celts have a better chance of competing at a high level in the future if they try to keep IT and add other talent, rather than trading IT simply because he's got flaws and hoping one of the younger guys takes his place.
My point is also that, by the same token, if IT were bigger, even if it didn't make one whit of difference in his effectiveness, he would be regarded as an NBA superstar who ought to be a fixture of the franchise for the foreseeable future.