League of Legends (LoL) Question: Brand

I'm not quite sure what you're asking. Are you having trouble playing Brand because of his low mobility, or are you having trouble playing against Brand? I'm guessing it's the former.

Use Conflagration plus Sear as your defense mechanism. If you land the Sear, you get a pretty sizable stun, which can help you live through ganks. Otherwise you just have to position well and use Flash to get yourself out of sticky situations. Brand's low mobility is one of his weaknesses, so it makes sense that it makes you feel vulnerable.

If you really don't like it, you can always try more mobile champions like Ahri and LeBlanc for mid lane or Karma for support.