Should I simply disregard my team and play an ad midlaner into an inevitably full ad team comp or should I simply give in and grow better at caster type champions.
That depends on your personal strengths and where you want to grow.
If you're the sort of person that wants to hard carry all the time, then you should focus on what you're already good at. A lot of mid laners have that mentality (and it can be a contributing factor to why you like playing mid lane despite not enjoying meta mid lane champs).
If you feel you succeed more helping your team out (acting as the team leader, roaming to get your teammates kills rather than yourself, focusing more on objectives than lane bullying), then adapting your choices can help a lot.
Either way will work, but it has to be because it's what you WANT to do. If you really want to hard carry with Talon or Zed, then picking up Orianna is just going to frustrate you and make you think "why isn't my team winning even though I diversified our damage!"
Also worth pointing out- diversifying your champ pool (to an appropriate amount) will help your standings only a tiny bit in the long term (unless you're a one-trick whose champ starts getting 100% banned due to meta shifts or something). Unless you're near the very top of the ladder, you have enough room for personal growth to keep climbing even if you only play one champ that doesn't fit well into normal team comps.
