Missing someone (but not romantic)
I would say you should be careful of using 我想念你 or 我想你 , especially to a opposite gender. Usually, we say 我想念你 or 我想你 jokingly to avoid the confusion, except saying it to your 'real honey'. 

But if you put 我们都很想（念）你， meaning you are missed among all of our friends, that would get you out of the confusion.