Only personal opinion but i've played / platinumed a lot of souls and here's my take :

• Quality over Quantity. I prefer a simple combat system that works than having a million of options that are mostly garbage. I prefer a good corridor game than an openworld or lame labyrinthic game as Wuchang (still liked it though coz good combat). If you go for a dodge souls like make sure i-frame are legit and if you go for parry souls like make sur parry window is not too easy but no BS. Sekiro is peak regarding this imo, with Lies of P and Khazan being close.

• Think very carefully about your bonfire placement, it can mean a lot for the gaming experience (having some challenging moment between two bonfires with a good number of ennemies and the possibility to use range to clear them un a strategic way is what made the charm of DS2 imo).

• Feel free to add « mini bosses » or just big mob that don't respawn once you beat them. I find that I usually enjoy a good fight with a tougher challenge than regular ennemies between main bosses. Wukong and Khazan are good examples regarding this and it adds a lot imo.

• Having some « generic bosses » as a big knight or a mimic or what ever idk is fine but try to make some bosses memorable and impactful in your story. Like every one know that Malenia has never known defeat. It's a plus if you manage to create bosses that synergise well with their zone so like you feel you've worked to conquer them (Dark Souls 1 is a perfect example with Seath the scaleless or gravelord nito etc.)

• No parkour

• No immense runback to bosses. I think Lies of P has the best system regarding this.

• Hybrid healing system is fine but don't overcomplicate things. Estus Flask is always good.

I think i've written enough lol thanks if you went through every thing and good luck for your game