I like the idea of Concentration, but it does seem like they went a bit overboard in how many spells use it. Having to choose which awesome buff to have up is great! But having to choose between having a buff vs enchanting an enemy vs creating terrain seems a bit harsher. And yeah, for True Strike in particular it seems awfully unnecessary.
Overall, I've definitely found it brings more good than harm. (Having just converted from a 3.5 campaign where we were getting into the "buff spells / arms race" paradigm of mid-high level encounters). But some spells seem like they could do fine without it, and for True Strike it especially seems ill-fitting.
In fact, I think that's what I've found in general for casters. The caster design as a whole works just fine, but they haven't quite nailed the individual balance from one spell to the next, and there do seem to be some real clunkers out there. (Witch Bolt, in particular, sounds cool in theory but has a lot of flaws preventing it from really being worthwhile).
That said, I think it also comes down quite a bit to expectations. Not just in terms of being used to the power level of casters from previous editions, but also the expectation of the purpose for individual spells.
For example, Scorching Ray in 3.5 was - especially once you got multiple rays - all about the single target damage. It was a great tool for wizards to unload a bunch of damage into a target. But I think trying to use the new one in that role will lead to disappointment. Touch AC is gone, so it is no longer super-accurate. If they do all hit, sure, the damage is decent - but as noted, not only slightly better than what a rogue might be doing in a regular round.
But on the other hand, if you use Scorching Ray when you are dealing with a large group of weak enemies, like Kobolds? Being able to split up your fire and potentially take out several enemies at once actually becomes quite useful. But if you don't run into fights that are great for it, it might not be as 'wow' as you want from a 2nd level spell. Particularly if you've already memorized spells for dealing with groups of enemies (like Burning Hands) and were really expecting Scorching Ray to fill a different role.
Nonetheless, if looking for a wizard to be a blaster of raw, focused damage, I don't think that's happening until higher levels, or without specific class features from things like evoker, sorcerer, etc. If you want to hose an enemy as a wizard, you either need some cool combo (drop a Cloud of Daggers on an enemy and have your friend keep them prone/stunned/grappled in the cloud), or you need to go with status effects. Yes, most status effects require a save and many of them will give the enemy a chance to break free after a round. Still, shutting foes down for even round can be a big deal. Particularly if you can cause some damage in the process (Ray of Sickness / Crown of Madness), or hit multiple foes (Web). Or just settle for a lesser effect (Reduce) that can reliably last the whole combat.
Now, all of that *is* different from how potent some spells could be in the past. In return, though, Wizards do get the consistent usefulness of Cantrips, plus improved survivability compared to the past - and some actually decent class features for once. It certainly isn't a trade-off that is going to work for everyone, sure, but I think a lot of them seeming to 'suck' may come more from errant expectations that it does from them failing to fill the role that this edition has envisioned for them.
Archer. They're just as competent in ranged combat as any other non-martial, don't need ammo, and have access to potent ranged damage, superior to that of a bowman.First off, thanks for a well thought out and detailed post. Kudos.
As regards to your last sentence, I'm still trying to figure out the role of a low level Wizard. Blaster? Not really. Controller? If so, not for long. Protector? Not much there either. Buffer? No. Debuffer? Nope. Iron Mage? That's totally out of the question without multiclassing. There are a few spells like Sleep and Illusions that allow for a little control, but they really are extremely situational. And yes, there are spells that allow for all of these, just mostly in a subpar way (with the possible exception of Sleep).
First off, thanks for a well thought out and detailed post. Kudos.
As regards to your last sentence, I'm still trying to figure out the role of a low level Wizard. Blaster? Not really. Controller? If so, not for long. Protector? Not much there either. Buffer? No. Debuffer? Nope. Iron Mage? That's totally out of the question without multiclassing. There are a few spells like Sleep and Illusions that allow for a little control, but they really are extremely situational. And yes, there are spells that allow for all of these, just mostly in a subpar way (with the possible exception of Sleep).
With regard to concentration, a side effect of it is that it also encourages wizards to "stay in the back where you belong". I have played a lot of Iron Mages starting with 2E and a lot more so with 3E and 4E, and that concept is almost totally gone. One really needs to be wearing armor to get there in 5E. Just using spells is mostly out of the question.
Archer. They're just as competent in ranged combat as any other non-martial, don't need ammo, and have access to potent ranged damage, superior to that of a bowman.


@OP - sounds good to me 0 playing the Starter Set the Wizard PCs had seemed well-balanced, but I was worried that with only 1-2 fights/day in my games they would be overpowered. Sounds as if this is not the case at low level, anyway.
Of their 1st level spells, I think the ones that have the most oomph are in the Controller / Debuffer role. Color Spray, Grease, Ray of Sickness, Sleep, and Tasha's all can have a solid impact on a combat.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.