Honestly, thats one of the weirdest parts of OlliOlli 2, in the first game you were able to use the analog or the D-pad, and like you said I preferred the D-pad for a lot of things because of the precision. Though certain tricks all but require an analog stick, so I guess they just got rid of D-pad support to prevent people from complaining that some tricks don't really work with it. Anyway, always weird to see an option that existed in the first game removed for the sequel.
That said, I absolutely loved OlliOlli once I played a bit and let the timings and controls "click". I also recommend for anyone to stick with one platform and not swap between Vita/PS4 if you have both, since the timing always seemed ever so slightly different, and the game is all about precision (may have just been my TV or refresh rates or something, dunno). But like anything else, if you stick with it long enough to go through an entire level with one huge combo and you beat the level's required high score by like 5x, it is a fantastic feeling.