[MENTION=57112]Gradine[/MENTION], you hit the nail on the head with the mechanical issues. Before the sorcerer can be fixed, though, we need to decide what it's niche should be. If you look at the 5e version it looks like they were trying to make magic mastery via meta magics the distinction. If you accept that, then the obvious fix is to make the sorcerer's meta magic abilities actually strong enough and prevalent enough to matter.
Yeah, I was thinking about talking niche but my posts were running long. If you think it terms of 4e roles (which are no longer codified but I think no less important), Warlock fills the "striker" niche, while Wizard fills the "controller" niche (and in general is better suited to utility). The problem is that this doesn't leave much niche left for the Sorcerer. I think there are two key points that need to be a part of the niche Sorcerer describes, and how to fix it:
* Theme. With their limited spells known, Sorcs better than any other spell-caster can fill the role of the thematic caster. D&D has always been such that versatility will always trump expertise, at least in terms of optimization, but there's a broad fantasy trope to fill here and Sorcerers are best suited to fit it. The problem is the limited spell list; Sorcerers are cut off from accessing the spells they would need to complete their theme, for really no good reason. The fix? Open up their spell list some. Or a lot. Give all Sorcs access to the Wizard list, for a start. From there, maybe archetypes? A fey bloodline could be the Favored Soul but for Druid spells. Infernal bloodline might hand out a few Warlock exclusives. A drop of siren's blood for Bard spells. If we aren't bringing Metamagic to every caster class, let's bring every caster to the Metamagic class.
* Adaptability. This is the big one, the one that's related to metamagic, and it's the main reason I think that Sorcerers fall short mechanically. The extra spell slot across the board helps fix this somewhat by freeing up more Sorcery Points for Metamagic. And this is really the key feature of the class; it's their Smites, their Rage, their Sneak Attack. I don't necessarily know that it needs to be stronger (I haven't gotten to see much use out of it myself in actual play), but it needs more options, and the Sorcerer needs to be able to learn more of them, and more quickly. Sorcs should start with Sorcery Points and two metamagic options at first level. The point of the Sorcerer, their true niche in 5e, I feel, is that they can do a lot with a little because of how adaptable they are.
Some ideas for new Metamagic Options:
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Energy Substitution - When you cast a spell that deals fire, cold, acid, poison or lightning damage, you can spend 1 sorcery point to change the damage type to another type from that list.
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Energy Admixture - When you cast a spell that deals fire, cold, acid, poison or lightning damage, you can spend up to 3 Sorcery Points; choose a different damage type from that list and deal an additional 1d10 damage of that type per Sorcery Point spent.
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Share Spell - When you cast a spell with the range of self, you can spend 1 sorcery point to make the range of spell touch.
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Share Burden - When you cast a spell with a duration that includes Concentration, you can spend 2 sorcery points and touch one willing creature with whom you share a language; that creature now maintains concentration on this spell.
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Imaginary Spell - When you cast a spell against a single creature that forces that creature to make a saving throw to resist its effects, you can spend 2 sorcery points to force the creature to make a Wisdom saving throw instead of the saving throw required by the spell. If the target succeeds its save, it resists all effects of the spell, and you regain the spell slot used to cast the spell.
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Distracting Spell - When you cast a spell, you can spend 1 sorcery point and use bonus action to Dash, Disengage or Hide this round.
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Shunting Spell - When you cast a spell using your Reaction, you can spend 2 sorcery points. After your spell resolves, you may teleport a distance up to your speed.
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Delay Spell - When you cast a spell with a duration of instantaneous, you can spend 2 sorcery points to delay the effects of the spell. You must choose a target or location for the spell at the time you cast it. At any point in the next three rounds, you may use your reaction to trigger the effects of the spell. You may only have one spell delayed at any given time, but you do not need to maintain concentration on a spell you have delayed.
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Sculpt Spell - When you cast a spell with an area that is a shape (a cone, sphere, cube, cylinder or line), you can spend 1 sorcery point to change the shape of the spell to a different shape (for example, you cannot change a cone to a cone) out of the following list: a 40-foot cone; a 20-foot-radius sphere; a 30-foot-cube; a 20-foot-tall, 20-foot-radius cylinder, or 100-foot line.
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Defiling Spell - When you cast a spell that targets a single creature, you can spend 3 sorcery points to force the creature to make a successful Constitution save against your spell save DC or suffer a single level of exhaustion. You cannot cause a creature to suffer greater than exhaustion level 2 with this effect.
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Earthbound Spell - When you cast a spell with an effect of instantaneous, you can spend 1 sorcery point to bind the spell to a 5-foot square of earth or stone. The effects of the spell trigger the next time a creature steps on that 5-foot square.
Some or all of these are likely to be a little to very broken. I'm not a game designer. But I'd like to see at least as much variety in Metamagic as there is in, say, Battlemaster maneuvers.