As a wizard you will have less mana than a sorcerer and cast your spells slower. I find that if I am careless with my spell casting that I run out of mana. On a wizard this is even more likely to happen (and I have a wizard alt, so I know it does happen).
IMO wizards would benefit from specializing just as sorcerers do. Many people feel that wizards should be jacks-of-all-trades because they can memorize every spell. If you try to do this you will run out of mana very quickly.
Most groups expect buffs from wizards, bards and clerics. They have much lower expectations from sorcerers. This has the unfortunate effect of putting most wizards into the buff role and it can eat up a large amount of mana. As a result, many wizards take on crowd control as their other function as area-of-effect spells that slow or stop mobs (so the melees can offer the beat down) are more mana efficient (you can web rather than firewall for less mana).
Realistically, there isn't much you buff as a wizard that can't come from another source (cleric or bard). So, taking a more sorcerer-like approach and becoming an offensive spell build should not be ruled out. You may need to let the group know where your focus is so that they do not look to you for their buffs and crowd control. But, once people know they should be fine with it -- unless you suck completely.
Since I get into groups all the time I'm sure you won't have to worry about that. I mean, if I can get into groups as gimpy as I am then anyone should be able to.
FWIW, always be ready to cast an emergency buff. And, remember that just because you CAN kill it doesn't mean you MUST kill it. Go ahead and let the melees have their fun too. Be stingy with your mana and you won't need to worry.