Sorcerer Warlock build concept and ideas

[Bagel]

so i've been playing 5e for a bit and have a concept for my second character:

sorc16/warlock4

so far i have it planned as such

human [variant] +1dex +1charisma,Skill proficiency: perception

stats: dm approved point buy
10str 18dex 18con 10int 16wis 18cha

Sorcerer: Dragon Magic [fire]
Warlock: Old One [Tome]

lvl 1-3 sorc
lvl 4-5 warlock
lvl 6 sorc
lvl 7-8 warlock
lvl 9-20 sorc

Feats:
human: warcaster
lvl 06: Polearm master
lvl 08: ASI +1dex, +1 Cha
lvl 12: Elemental Adept [fire]
lvl 16: ???
lvl 20: ???


any input or advice would be appreciated.

[Osiris]

so i've been playing 5e for a bit and have a concept for my second character:

sorc16/warlock4

Feats:
human: warcaster
lvl 06: Polearm master
lvl 08: ASI +1dex, +1 Cha
lvl 12: Elemental Adept [fire]
lvl 16: ???
lvl 20: ???

Looks fine overall, but I feel the need to point out two points:
1) shouldn't the Polearm Master feat go to you at level four? In my campaign, feats/stat boosts happen every four levels regardless of class (well, except fighter).
2) Why not Sorc 17 / Warlock 3? If your DM is strict about what I have said above, I can see why Sorc 16 Warlock 4 is a better choice. Do note that you are not getting 9th level spells. Anyway, why Warlock? Is it for the Tome? Is it for the Great Old One?

[Amnoriath]

Why are you taking Polearm Mastery for? As of now you don't get the good polearms and you don't have an Extra Attack. Also there isn't a single polearm that has the finesse property. Please tell us your concept of the character here because it seems like you choose this for options while sacrificing effectiveness.

[SharkForce]

i'm assuming he's going to take shillelagh with tome lock.

that said, why 4 levels of lock? that ASI isn't doing you a huge amount of good, from what i can tell. 1 extra cantrip (between sorc base cantrips, lock base cantrips, and tome cantrips, you should have more than enough already) and 1 extra warlock spell known (and their spell list isn't *that* good).

in contrast, you lose out on eventually getting level 9 spells (which is a relatively minor concern, because you may very well never reach it in the first place), and you delay all your sorcerer goodies (which is the real problem); you'll have to wait longer to cast the best spells, and you'll start off with fewer points and less room in your pool.

honestly, even the 3rd level of lock feels a bit much until level 20, if it weren't for the fact that you are (presumably) wanting to have an effective melee attack somewhere earlyish in your adventuring career.

[Bagel]

the polearm master/warcaster/shillelagh combo is the point of the weird progression. i am fully aware that with this class combination i'll never get 9th level spells but i don't expect to play this character beyond 12th level. this character sin't so much about optomism as it more about concept. with shillelagh i can cast it on a staff focus being used as a quarterstaff and then make use of the warcaster's spell replacement for AoOs in concjunction with repelling blast to not be useless in melee. Spell sniper seems like an ok feat later to get rid of the firing into melee drawbacks for Eldritch Blast.

[SharkForce]

just so you're aware, you'll be making that eldritch blast in melee range (from warcaster opportunity attacks) at disadvantage unless you get crossbow expert, which otherwise does absolutely nothing for your character.

also, there's a twitter ruling out (that may or may not be official and that may or may not become official) that the opportunity attack from polearm master must be made using your polearm.

also, i'm still not getting why you would take the 4th level of warlock. what benefit is it that you're looking to get from the 4th level? the third level makes sense, but i feel like the 4th level just pushes back your character's progression... remembered something that made the sentence that was formerly here completely inaccurate, so i removed it