Yes and No. Individually, mages are in a fluctuating good/bad state.
Items are really where they've been hit. It's been this way ever since they removed all mana regen itemization from mages.
MAGES NEED TO SUSTAIN THEIR MANA. It's their core output. I've run out of mana a few times more lately than I have ever before.
Meanwhile, other roles tend to have a certain wider access to tools. Tanks have a large amount of flat mana and low mana costs (with exceptions). ADCs are mana-heavy if you spam skills, but they have auto-attacks for dps and a significantly better set of items to compensate when they choose to be mana heavy. Junglers have blue and don't really share anymore unless they're ahead, since that literally wipes their experience and gold. Then you have supports with ALL THE MANA REGEN... who still run out of mana when they have to:
"OH GOD GOTTA SHIELD EVERYONE AGAIN, DEAR GOD WHY DID YOU GO INTO THAT AGAIN?! I HAVE 10 MANA WHAT DO I DO NOW!!?"
(Early game Sona is a very good example of this. Fortunately, you can usually pace yourself against this, but it's still a problem when you need those skills RIGHT NOW.)
It's a significant and distinctly problematic concern. It pairs with the other issue of CDR being predominant. There is a shift that focuses on more casts faster, but capped by your mana pool. Even Morello's is a joke in this regard, because you actually have to GET THE KILL/ASSIST to get the mana back.
Now pair that with a very high cost itemization, some of the most costly items in the game. You are not able to buy the items you need at first because you need the ones that sustain you through your lane. Then after you get those and can finally buy the core items you do need, you end up behind in DPS. Latest-game, when you are fully itemized, you lack the ability to really get through the durability of champions who build very little of it.
Here's the kicker:
It's already been a thing that has come up, specifically in relation to manaless champions. They consistently become very difficult to balance because they can skip the mana items. Hence why most of them end up trashed or lacking just the right amount of power. Comparatively, they skip the sustain-gap and go right for the core itemization. So when core itemization gets tweaked for the better, they get broken.
Until Riot addresses the sustain gap with tools to mitigate it, gameplay will be a swing in regards to how mages feel.
used to stack up to 650 hp, 650 mana, and 80 ap for 2800
had 500 hp and 80 ap for 2900
was only 3300 but it had 5% less ap
was the premier mana sustain item before it got forced to be a support item
used to be 3200, but had 120 ap, 50 armour, and stasis only had 90s cd
used to be 3000 and has a 0.75 ap ratio
Meanwhile adc have had way buffed itemization
used to cost 3800 but had 25% crit chance
didn't exist back then
used to be a pure on hit item with 70% as and no crit
used to cost 2800 and no damage reduction passive
used to cost 2500 and did way less damage
didn't exist
used to only have 5% current hp on hit but had 15% lifesteal
as the exception.