I had two new players join in the 5e era. First one played a bard and the second a warlock. I got nothing against a simpler fighter option, but I would still like the champion to have a little more meat to it. B
I always chafe a bit at calling the fighter "simple" vs the caster "complicated."
In reality, especially in the beginning generation stage, the fighter's player is faced with much more complex and difficult choices than the caster's player - and they have much broader ramifications going forward.
Let's start with stat generation:
The wizard puts his highest stat in INT (unless there's a roleplaying reason he doesn't want to, but that's outside this scope) - boom done - the rest is preference and window dressing. INT will allow the wizard to be the best wizard he can be.
The fighter has to FIRST decide: Best stat in STR or DEX - this will have ramifications for the rest of the build.
If DEX then do you dump STR? you can, but Athletics is the fighters most obvious way to interact with many exploration challenges, so that's tricky. If STR, dumping DEX has serious consequences too (you can't supplement weaknesses with spells like the wizard can). And unlike the wizard, you have to concern yourself dumping WIS and CHA too because stats are the easiest way you get bonuses in a pillar other than combat. And god forbid you don't prioritize CON, low CON for a martial is dangerous (more so than for a caster, even with concentration).
Then the fighter has to make the choice of melee or ranged. Very difficult to be fully competent at both, even with a DEX build. Again choices matter here and will have ramifications for the long haul. The wizard doesn't really have to worry about this choice.
Then skills. The fighter has to pick carefully as they can't supplement without help. Pick a "fun" skill - it's at the expense of something else. Sure the wizard has this problem, but they can supplement with magic (need to descend a cliff and are lousy at athletics - you probably have room for feather fall on your list).
And it goes on.. and that's just to 1st level!
Further if the fighter picks poorly, he's stuck unless the DM is kind and lets him redo (there are now SOME options to swap out styles and maneuvers, but it's still a wait). The mage may be stuck with some subpar spells, but they can fix at every level and I've never been in a campaign where the DM has been all that stingy with spell acquisition (I'm sure they exist, but I haven't see it!)
So I'd say, in many of the ways that matter, the "simple" fighter is actually more complex than the wizard.