I enjoy playing artificer, and would like it to be updated for One DnD. That's a pretty good reason to have an arcane half caster.
And classes not in the initial PHB are side-lined and forgotten by WotC. Hence artificer in 5e having barely any content.
At least that's a logical reason I can respect! I'm not the biggest fan of Artificer but it's not a disaster either.
Strong disagree.
Until 5e, every bard has capped out at 6th level spells at most. They have never been full arcane casters (aside from 4e, but that's hard to compare against the other class/level formats in this case). 5e definitely flies in the face of the "jack of all trades, master of none" theme of the bard, as reaching the pinnacle of spellcraft - level 9 spells - is pretty definitively mastery of casting.
If any existing PHB class fits the role of "gish" arcane half-caster, it is the bard.
This is not a compelling argument on any level.
There have been four editions where Bard was a proper class (not a weird dual-class thing or an optional class from Dragon). 2E, 3E, 4E, and 5E.
2E - Advanced extremely fast, to the point where you actually got fifth-level spells before a Fighter/Mage did. Were more than a "half-caster". A 2/3rds or 3/4s caster, which is more appropriate. Was a true Jack of all Trades.
3E - The only edition where the Bard was a "half-caster". Also the only edition where the Bard was a
trashfire. All negative Bard memes originate with 3E, because 3E's vision of the Bard was absolutely idiotic. Only the fact that being a caster was a huuuuuuuuuuuuge advantage over not being a caster saved them from being bottom tier. But a failure on every possible level.
4E - Bards were, as much as anyone, "full casters", with a huge suite of magical abilities, and bloody effective ones too.
5E - Bard are full casters. Jack of all trades but master of none is NOT a viable design for a
balanced class in 5E, so they actually got good at casting and were made less of a joke-class than 3E.
So 50% of editions Bards are full casters, 25% they're 2/3rds or 3/4s casters, 25% they're 1/2 casters. Seems like your
own argument suggests they should be full casters based on that logic. You can't just exclude 5E because it's current lol.
As for "Gish", Bards are absolutely not your "Gish". A Gish is a Fighter/Mage, not a Bard. Magus would be your Gish if anything.
But in the last 30 years or so, magic swordsmen became more and more popular. Mostly from comics, cartoons, and manga. And a class emulating those tropes would fit D&D.
For example, I chould take the 10 most popular Shikai Releases from the manga/anime series Bleach and create 10 new arcane spells for a potential AHC that would be fitting for many settings.
100% agree!
D&D is definitely missing it's "Swordmage" or Magus type!
100% disagree that they should be an "Arcane half-caster". None of those characters are half-arsed Wizards who are also not great Fighters.
Like I said, the Warlock chassis is much better for characters like the ones you're describe. Yes, give them new spells, but give them the Warlock chassis, not an "Arcane half-caster" chassis.