He is absolutely a good fit for his style, and is a decent if unexceptional player. That's the problem. He's not good enough to build a team around, and frankly he should have been scoring many more goals than he's managed. If you want to build a team that will be competitive in all three competitions, then you simply *need* someone better.
Also: even if instead we replace Thomas with a much, much better player (which we also should) - Lucescu will gravitate to Oliveira as backup over Tzimas, which feels like such a waste. Coaches shouldn't be allowed to hold on to their teddy bears forever.