I'm starting a 4 person campaign with some friends, and everyone has picked their character but me. So far, we have a halfling open-hand monk, a tiefling lore bard, and a human druid (eventually going to MC barbarian for tankiness. Started with sentinel.) I'm hoping to balance out my part a bit, and was thinking about an offensive caster (the druid is going to spent most of her time in beast form and most of her spell slots on self healing, and the bard is more a support and control caster than anything). I was thinking either a forest gnome wizard or a half-elf sorcerer. I know that wizards have more utility with their spellbook and rituals, and that they can match dragonblood sorcerer dps if they go evocation, but my gnome is built (both as a wizard and as a character) more to a flavor that I think will be really fun to play and roleplay. On the other hand, the sorcerer does have alittle more offensive edge with metamagic and sorcery points, by sacrificing that spell utility. It is a more offensive caster that might round out my party better, but with our tiefling bard I don't know if the party would benefit as much from a Cha-based caster as it would from an Int-based caster. What do you guys think?
Always be yourself!
Unless you can be Batman
Then always be Batman!
In other words play the Wizard.
I think INT won't do the party much good since it's only used for investigation beyond lore skills, and the bard's jack-of-all-trades ability applies to those lore skills anyway, so the benefit for INT is rather limited. I also think control and status effects are good, at that bard can pick up some AoE's for when they are applicable. The wizard is the better controller (IMO) but they can still do similar things.
I would likely make a rogue or fighter to join that group since a bard and druid cover spells pretty well but it looks like the druid is covering melee mostly, and the bard gets left with combat healing as part of the contribution that can take away from controlling spells or damage if selected with secrets; like you mentioned the bard appears to be filling support. It sound like you want an offensive caster and I would add warlock to your list of options. Bards and druids cover versatiltiy and utility, and both also have options for controlling effects. Even with the druid pushing towards melee and the bard pushing towards control and support there's a large overlap with both on the wizard, even an evoker.
A sorcerer has sorcery points and those are potent. A warlock (go tome) has very strong sustained damage with eldritch blast at will and benefits better from it. Using invocations for at will spells or spell selection help with utility, and the large list of cantrips and ritual book available to tome warlocks increase that versatility. Out of wizards, sorcerers, and warlocks, warlocks are my personal favorite.
What calls to your creativity and sense of wonder? Always choose that first, regardless of what anyone else is playing. Play the Wizard if you think that'd be fun. Bump his Cha and multiclass WM Sorcerer a bit if you really wanna have some fun!
D&D isn't a video game. If no one wants to play a dedicated healer, then you'll still figure things out that work for your party.
If you want a pretty rad offensive caster, check out Tempest Cleric. Max damage Thunderwave and Shatter at low levels ain't nothin to sneeze at.
Based on what you have written, you seem most drawn to the Forest Gnome Wizard character...and if that is what you truly feel, then that would definitely be the one to go with and provide you with the most enjoyment. 
Thanks for all the input, guys. I had a decent bit of background drawn out for both of my initial options. One was the eccentric gnome wizard, powerful but a bit scatter-brained at times. We're doing the HotDQ campaign, so I chose one of the optional backgrounds for him as the dragon researcher - obsessed with draconic knowledge, history, anatomy, language, etc... The second was a brooding but good-hearted half-elf sorcerer whom I gave the other background option as a gold dragon who was cursed to a humanoid form by Bahamut because of pride, memory stripped and given the chance to redeem himself. I was thinking about multiclassing warlock for Chain, eldritch blast, and evocations, and having an "imp" familiar that was actually a physical embodiment of his past life's pride and ambition.
I think I have decided on a mix of the two, starting with a Wiz 1/ Sorc 1 gnome with a bit of both backgrounds (but only the dragon researcher feature). Still obsessed with dragons, but also in reality a perma-polymorphed dragon, which surfaces in his levels of sorcerer. Focused more on int because of the better utility granted by the spellbook, and taking the no-save, no-attack roll (mostly non-ritual support) spells with my granted sorcerer spells so that I don't have to worry about a low cha score (it is 13). Still have half a mind to dip a few into warlock as well, just because eldritch blast is that good, although that would require a higher investment into Cha (which I might end up doing anyway so that I can get to Sorc 6 and add charisma bonus to fire spells... What if I went evocation too, and could add int AND cha to evocation fire spells? Holy crap, scorching rays just got that much more OP.... Though only at lv 16.)
Starting stats are 8/14/12/17/10/13, and starting with perma-mage armor will definitely be nice!
Other question, given this start-up, what are the perks of starting as a wizard vs as a sorcerer? The only real difference I can see is in save proficiencies. Gnomes already have advantage on Wis, Int and Cha saves against magic (which is the only reason I left Wisdom at 10, otherwise I would have done 16 int/12 wis). Starting Wizard would help fortify my wiz save on top of gnome cunning. Starting Sorcerer would give me charisma save proficiency, but I do plan on eventually taking battle caster.... I guess it eventually boils down to do I want Proficiency and advantage on wisdom or constitution saving throws? :/
Writhani wrote:
Writhani, as I've heard explained to me before, the best way to see if you want Sorcerer or Wizard is do this:
Look through the Wizard and/or Sorcerer Spell lists. If you find yourself picking 15-20 spells that you simply "must have" but don't really want/need the others, then Sorcerer is the choice for you! If, howeverm you see everything as a giant grab bag of utility that you'd like to have access to at some point, and/or you just can't get enough spells? Go wizard. As Mello said, wizards get more spells and given enough prep time (say, 8-ish hours) will often have the perfect solution to any problem if they planned ahead. But if you want to have a few select spells and can live with JUST those, then you can pick Sorcerer and be the best at casting those spells!
Then there's also the "non-spell" stuff to consider, but that's comparing Wild Magic, Permanent Mage Armor, Dragon Wings, and stuff to Ritual casting. So worth factoring in if you REALLY want dragon wings, but not exactly necessary when the main idea behind both classes is their spellcasting! Anything you get other than that is just a bonus!