UngeheuerLich
Legend
I like to have both options.
My favorite however in a possible 6th edition would be having base classes and subclasses more equal and that yoi can forgo your subclass to get a second main class. Both without subclasses then.
And when that is done I would like to have a feat now and then to pick up a few features you have missed.
So you might be a Wizard/Invoker
Or a Fighter/Warlord
Or you migh just be an ordinary Fighter/Wizard.
Then you might pick up a feat that gives the Wizard/Invoker some fighter abilities.
A feat that allows the Fighter Warlord to do some magical tricks. Or a feat, that allows the Fighter/Wizard to have some Invokation or warlordy fighting style... Or pick up the basics of thievery on top.
That would be very flexible.
If you put it on the 5e chassis,
You could have following progression:
1: Class ability
2: Subclass ability/second class
3: feat/ability score increase
4: proficiency bonus increase + learn a noncombat feat
Repeat!
The level 1,5,9,13,17 features are basic class features. Problems may arise with 9 spell levels on 5 increases. A possibility might be the use of feats to increase spell levels at that point. Maybe with a +1 increase in a stat. Probably you might always increase stats by 1 as a general rule. If you take ASI maybe you can increase a single stat by one, second one by 2 points.
My favorite however in a possible 6th edition would be having base classes and subclasses more equal and that yoi can forgo your subclass to get a second main class. Both without subclasses then.
And when that is done I would like to have a feat now and then to pick up a few features you have missed.
So you might be a Wizard/Invoker
Or a Fighter/Warlord
Or you migh just be an ordinary Fighter/Wizard.
Then you might pick up a feat that gives the Wizard/Invoker some fighter abilities.
A feat that allows the Fighter Warlord to do some magical tricks. Or a feat, that allows the Fighter/Wizard to have some Invokation or warlordy fighting style... Or pick up the basics of thievery on top.
That would be very flexible.
If you put it on the 5e chassis,
You could have following progression:
1: Class ability
2: Subclass ability/second class
3: feat/ability score increase
4: proficiency bonus increase + learn a noncombat feat
Repeat!
The level 1,5,9,13,17 features are basic class features. Problems may arise with 9 spell levels on 5 increases. A possibility might be the use of feats to increase spell levels at that point. Maybe with a +1 increase in a stat. Probably you might always increase stats by 1 as a general rule. If you take ASI maybe you can increase a single stat by one, second one by 2 points.