Adding a level of rogue to your sorcerer will make him less effective in melee combat, not more effective. That one level will grant you the ability to do 1d6 sneak attack damage, which will very rarely come up. It will however put you eternally down 1/2 a point of base attack bonus and will put your higher level spell acquisition back another level (and there are plenty of spells an arcane caster can cast to help them melee more effectively).
You really shouldn't be trying to melee with a sorcerer anyway, not unless you are going for a very specific character build. Since your party includes a hyperactive melee character I would simply suggest largely concentrating on spells that aren't area of effect or at least having a good enough mix that you aren't stuck with nothing to do.
Good point - and you can still control the battlefield with a good use of non area of effect spells. Maze or Otto's Irresistible Dance at level 8. Horrid Wilting is a big damage spell and is also targeted within a big 60 foot area.
For lower level spells, Telekinesis or Wall of Force have no save and can help control the field. Baleful Polymorph can be deadly if used right. Just imagine the barbarian charging into battle with 3-4 foes, only to have one be turned into a newt. Even if he gets better, it will mean the bad guys' mage or cleric had to use a dispel magic on their turn instead of using an offensive ability against the party.