It really depends on who would be against. If your against a strong early to mid game champ (such as Jayce), or someone who has great wave clear (like Mordekaiser), you will simply get wrecked. But, if you're against another late game champ (like Dr. Mundo), it would be a fairly easy lane.
However, the reason why Kat is usually sent mid is because she is an assassin, and assassins normally start snowballing off of kills on bot lane. If you send Kat top, you really only have your farm to rely on (you wont be killing your lane opponent early on), and you really take away from her damage potential if you build any sustain items.
Is she a very liable top laner? No. Can she go top with some success? Absolutely. Ive played Nasus on top against LeBlanc once, and it was annoying as hell! You would basically be that annoyance to your opponent.
Katarina gets destroyed by almost every top laner. If the enemy top is a tank then she can't get her snowball going. I would say that Kat is solely meant for mid lane and I would not suggest playing her in different lanes.
However, the reason why Kat is usually sent mid is because she is an assassin, and assassins normally start snowballing off of kills on bot lane. If you send Kat top, you really only have your farm to rely on (you wont be killing your lane opponent early on), and you really take away from her damage potential if you build any sustain items.
Is she a very liable top laner? No. Can she go top with some success? Absolutely. Ive played Nasus on top against LeBlanc once, and it was annoying as hell! You would basically be that annoyance to your opponent.