Yeah that's kind of what I'm currently considering. Initially, my main issue with Shifter was that it's actually worse than other druids during the shift, without spellcasting. Even if you're not going to spend much time of the shift casting spells, being able to cast a quick healing spell, or renew an ongoing buff or aoe spell is really nice, and it hurts to lose that playstyle / convenience after going through the first Pillars where it was possible, even with a shifting-focused druid.
But after exploring some other options, and looking at what people say (over there on reddit as well), I think I'm fine with the idea of no spellcasting while shifted (for a Shifter), if we make shifting itself much better and more flexible. We just cannot do both (allowed spellcasting AND flexible shifting) as it would require some alternative penalty for this subclass, such as removal of at least some (if not all) bonus subclass spells - and that is a little too much. Also, someone raised a valid point that with allowed spellcasting and unlimited shifting, it would become better to just always stay in a beast form and basically be a faster and more tankier druid, while casting spells - and it would also remove some of the theme and actual fighting purpose of the beast forms. And on the other hand, there's still a problem of armor and weapons PL bonuses not persisting through Spiritshift, and unless we fix that (which is a monumental task in the scope of the whole game, unless we tackle only a few most important items), it will still be better to drop the form to gain the increased PL and cast spells. So it's kind of not here nor there.
But if we keep not allowed spellcasting, and make shifting unlimited, then you can always drop the form, cast the spells and shift back. Which is not such a huge penalty anymore - and more importantly, at least for me, doesn't make you lose the current beast form (for the remainder of the fight) if you have to cast a quick spell - which was one of my issues with the subclass.
So this is where I am; I'm fine with no spellcasting, if Shifter has an actually better shifting. And when I say better - it should be much more flexible, and without limitations - not that the beast forms themselves should be MUCH better. We don't want to make druid a better fighter than other martial classes. As other martials have their different niches, Shifter could be able to adapt to the combat situation, by choosing the right form - with similar features to other classes maybe, as needed; and be able to switch between them back and forth.
As an example how it would it work,
- start the combat with some spells, shift to Cat form to deal with casters
- then shift to Bear form and off-tank a little bit
- then switch to Stag form to deal with a pack of enemies
- then switch to caster form, renew some spells, cast some healing
- switch back to Bear form - as maybe your main tank died - wait until you get healed back up and main tank gets revived
- switch back to Cat form to deal with a boss