cbwjm
Seb-wejem
The problem is comes from several issues:
First, sorcerers are presented as being masters at manipulating raw magic through metamagic that no others are supposed to be able to do yet the metamagic options are limited as the sorcerer does not get enough to not just pick the couple that are the best. Second, their spell list has some utility but nowhere near the other primary casters, to say nothing of that they dont have enough spells known to pick both them and thematically appropriate spells even if they did. And third, every other element *except* gold/red dragon sorcerers is lack luster due to most elements not having enough spell options, despite there being multiple archetypes of sorcerers devoted to elemental themes origins (dragon, storm, and arguable shadow as there are no shadow-themed spells outside of the one blade spell at 2nd level that are not homebrew). That altering a spell's elemental damage type isnt a metamagic is absolutely insane. As are origins that use spell points to activate their abilities while metamagic and creating spell slots use the same resource.
Fire sorcerers and Divine soul sorcerers are fine, great even. Lightning and shadow sorcerers are decent. Every other sorcerer build is lackluster at best. What annoys me most is that it's near impossible to roll a decent illusion or enchantment themed sorcerer despite the plethora of folklore surrounding sorceresses who do just that simply due to a lackluster and poorly thought out spell list.
I do agree that they could have had more elemental themed spells on the list, it's part of the reason why I opened up all thematic spells for a sorcerer's bloodline. As is though, altering spells has to be one of the easiest things in DnD. Burning hands and scorching ray could easily be themed for any other element. This may not be an option if you are playing AL, but in a home game, I'd be surprised if most DMs wouldn't allow it to be altered (mind you, from some of the horror stories I've read about DMs, maybe I shouldn't be surprised).
Sorcerers also have quite a few illusion and enchantment spells. Between the two schools, every spell level has at least 1 spell available to the sorcerer, most spell levels have more. If you did want to make one that focused on illusions exclusively though, then your spells are going to top out at 6th level.
I recall that mearl's mentioned that the activation of class abilities using sorcery points was something that rated quite poorly for the sorcerer which is probably why these abilities have been kept to a minimum for later bloodlines. Other than draconic which requires 5(!) points to activate their fear ability at 18th, I only spotted 2 others that spend sorcery points. Celestial which effectively gains an improved version of empowered spell for healing magic and shadow which allows you to cast darkness for 2 sorcery points which is effectively just casting it with a 2nd level spell slot anyway but with the added bonus of being able to see through the created effect.