The biggest issue with the Hobbit Films was that Jackson had less time to work on them as a whole vs LotR. Jackson supposedly wanted to do one Hobbit film, Studio wanted Two, Jackson filmed enough for 2(+Extended Editions), but then WB went "JK we've planned for 3" and Jackson was left to try and stretch one book he had filmed into 2 parts over 3 films.
Honestly, while the films aren't as good as the OT, they're definitely not "bad". The issues stem from Jackson wanting to Wield the Hobbit's era to LoTR, but having nowhere near enough time to work with the changes.
If Jackson had been given until 2014( as opposed to under 2 years to rewrite what Del Toro had, replan, etc) The Hobbit would have been better for it.
That said, The LotR Trilogy is a fucking Masterpiece of moving parts in a genre that (regrettably) is full of shit. That it turned out good was thought impossible: that it turned out the way it did was a miracle.