Hmm context needed. It depends on who you're going to say that to. --------- 君 is normally used by guys to address a girl. As you might know, 君にあいたい and あなたに会いたい literally mean 'I want to see you'. They would sound like you're romantically interested in that person. You'll never say 君にあいたい in normal conversation to mean 'I/we miss you' to your ex-coworker who has left your office or company. ------------ Btw it's ありがとう not ありがとお.

君に会いたい。= I miss you.