J Smoove will definitely upgrade our team. Just based on facts alone, I'll take a guy 19 and 10 guy on my team with open arms. Now moving on from facts, he's also an elite defender, which is an area that most people think he succeeds in because of his athleticism. The truth is Smith has the hops, the quickness, and also the skills of a dominant defensive big. For one he's an excellent pick-and-roll defender. He has the length and the strength to match up against other bigs and also the quickness to guard wings. I wouldn't mind having him and KG anchoring the low post. Both of them will be able to communicate and call out signals. There's no other Celtic that has his level of talent and versatility on the defensive end, aside from KG (who's not as versatile on switches as he once was). Offensively, he's a decent player on the block and a nightmare in transition.
Bottom line is this. Our team is very good as currently constructed, with depth in all 5 positions. But when the playoffs start, starters will be asked to play longer minutes. Lebron, Wade, and Bosh will all play 40+ minutes a game and I can't imagine our second unit, as good as they might be, will be able to hang with the Heat Big 3. Adding Smith gives us star power, a point that I've mentioned numerous times in previous posts. A team with good depth will win regular season titles, but not championships (the Mavs of 2011 being one exception). Heck, just look at the Spurs these last couple of years. Those Spurs teams were deep, but when the playoffs came around, their bench couldn't compete with OKC or Memphis for that matter. I'd take Smith playing 40+ minutes in the playoffs over playing Bass 25 and Sully 23 all day.