First off Th9 was widely considered the most balanced Th level. And I would agree. It was also considered THE home for non ♥♥♥♥♥ing war enthusiasts. I must also admit to seeing way more 3 stars post update but this also happens to be at the same time my clan is really upping their game.
Its why I left Th8. Figured 3 star was just too easy. 30 extra seconds and a free spell slot. No real challenge.
But Th10 is a poor poor replacement.
But lets look at why.
What are the biggest 3 star comps for Th9?
Lets simply and state that Loons and Hogs are a huge part of the overall 3 star strategies present at Th9. Why? Because you can predict and plan with them. Sure other troops are used and are very important for the overall strategy, but Loons and hogs give you that surgical factor. They allow you to turn a blunt for GoWiPe into a 3 star strategy (or allot of Valkyrie tactics

)
Th10 gets the following troop upgrades
Tanks: Golems, LH, and Giants
Big but Slow Troops - PEKKA, Dragons
Farming Troops - Barch and Minions
That is it. The true cornerstones of a war army are capped at Th9 and yet Th10 gains the strongest defensive tower in the game and a huge number of point defense upgrades.
The end result isn't only that 2 stars are the norm but that their is a distinct lack of diversity. Most Th10 attacks are penta-golem-ish things. Occasionally someone pulls out a GoVaLo but that is a seriously difficult to master strategy and isn't going to work against any old base... which means veteran Th10 players aren't going to leave their Th10 open to common 3 star methods (such as AQ walk/charge)
Which again would be fine and dandy if we still could and needed to use a variety of attacking strategies. As it stands, your better off just spamming golems with wizards behind - the correct number of jumps and you'll get a decent percentage and 2 stars.
Its dull
Honestly after I got my warden to level 5, I'd say forget Th10. Max Th9, master taking down Th10 bases as you get the basics from Th10 (troop upgrades, camp, etc) and then head straight to Th11.
At least you get the warden's health boost and invisibility ability. Its freakin' sweet.