In my opinion, Warband's system was quite limited. There are optimal purchases that you should make, with the majority of gear being simply ignored.
Ah, so you're taking the competitive angle again. Of course, the far more populous casual side of the game doesn't really care for optimal choices nearly as much.
Now, even if we ignore that fact, I can't help but notice that this has far more to do with how the gear is balanced than any underlying system. Clearly, the equipment selection in Warband just wasn't up to scratch by your standards then, and therefore the key would be to come up with new ways to give unpopular items an interesting niche, rather than throwing out the baby with the bathwater.
Ultimately, a small minority of highly optimal choices always will exist. They sure do in Bannerlord, and there ultimately isn't that much you can do against it.
It is also possible to eliminate most of the drawbacks of any of the classes (inf, ranged, cav) by swapping gear with teammates (and please don't get me wrong, I love the teamwork and communication involved in gear swapping, I'm just not a fan that there are few, if any, downsides to it).
Again with the competitive rubbish. I don't give a rat's arse about competitive.
Your system ruins casual play with its sterile, boring nature, and you've yet to win the established competitive community's support anyway.
Casual players basically never gearswap, not that it really matters when they do. Besides, much of this could've been adjusted by changing the various stats on the individual classes to adjust what they can use, and how well.
The class system presents you with a meaningful choice
Yeah, which of the very few non-rubbish perks should I pick?
that you have to make with each spawn, taking into account your own team composition and that of the enemy. This choice can then be further tailored through perks.
Let's be honest here, the viable options at the moment are fewer and further in-between than in Warband. If you manage to solve this, I know that you know it'll have far more to do with time taken to balance things, rather than any underlying traits of the system itself.
If you provide a free selection of gear with plenty of viable selections, then you will obviously have a far more interesting variety of options, combinations and choices than the current system could ever provide.
In Warband, I've picked an immeasurable variety of different loadouts over time depending on budget, map, gamemode, and so on. Fine-tuning, tweaking and adjusting things just right to be the most effective, or just the most fun at that moment.
All of this fun, and (arguably far more important for MP),
replayability has been tossed out of the window with your stale, samey system.
The amount of things you can do with the Warband system is staggering, especially considering how utterly basic it actually is. That you decided to throw out all of this potential is just insanity. You could've built on the excellent foundation that is the Warband system to create something incredible, instead you decided to build on an incredibly shaky one.
Now, I'm sure you want to say that you'll say that Warband has a major flaw, in that for example, you can always get a good shield as infantry, unlike Bannerlord where many two-hander troops don't have such an option, or can only get a tiny, crappy one.
However, this doesn't really hold any water, as you can see by people suggesting that every class should get a the option of a shield - you are not providing interesting choices, you're merely providing mechanically non-viable options. If you make what used to be non-viable viable, then this is again far more likely to be an issue of balancing gear, rather than the underlying class system.
Obviously, perks and classes still need some work, there is no doubt about that, but eventually, I think they will provide players with a fairer and ultimately better MP experience.
I feel that the only missing ingredient is the visual customisation that Warband offers, allowing players to inject their own personality into their character.
The only "unfair" thing about Warband's system, that of "Snowballing", or having more money than others, isn't even fixed in Bannerlord. In fact many have argued that it's gotten far worse in Skirmish. Not that many of us ever considered it a problem in the first place.
To limit customisation to superficial aspects is a non-solution. Not only that, but that instant recognisability of classes that you used to proclaim was oh-so important (it isn't, and you haven't achieved it anyway) would go even further down the drain.
Look, your system just can't provide what people want. I know you're invested in it, but that's just how it is. People aren't disliking it out of habit or nostalgia, it's just that you can't see what the community sees.
An alternative is desperately needed.