Hi,
I've been a student for over 40 years

, so I know whereof I speak.
I played Beethoven no1 as a high school/college student, and I think that one is a great one. Mozart no17 (K453) is gorgeous, and technically not too difficult--although interpretively quite challenging.
Although Mozart K488 in A Major is pretty straightforward, I thought the 3rd movement was tricky. Same goes for no 14, K449 in E-flat. Also have played no 19, K459 (F Major) , and the first two movements are not difficult, but oh, the 3rd one. (Great for those who want to work on velocity and clarity!)
That said, I believe all the Mozart concerti are very difficult to pull off well, more than the Romantic works.
All the best, Teresa