The "weight" of the character is the best feature. In all other games, the characters feel feather like light. In TS3 they feel humanly heavy. You needed to master the movement to make them feel light. Aesthetically, the animations may have got slightly better for TS4, but there is WAY less of them available and they all very similar.
Graphics improving is a obvious thing, but when com paring to TE....rather not.
As far as serves and aces, return took time to master, but it was possible to to allow aces for an entire match. It all depended on a skill. TS3 allowed for Various skill sets to be developed by human players, you can be great at returning and suck at serving, or be a great mover but horrible at risk etc... each human opponent felt profoundly different, you can see the style immediately. Something TE and TS4 do not have, or rather much less pronounced.
TS4 sucks. Plain and simple. TE is a great game, no doubt. But TS3 is still the king on Console tennis to me. A game with ultimate, never ending depth, skills that literally took years to develop. Unlike in TE where one with quick fingers can be competitive within a month or two.
Anyway, its all a preference, you don't have to like TS3, but since you didn't even scratch the surface with this game - I don't think you should be passing judgments, but then again it is an open forum, so go ahead.

Level 13 Edberg and counting...