Sure, you could take feats out of 3rd edition, if you want to suck all the fun out of combat and character building. Honestly all of these ideas are terrible. 3rd edition does not need a fix, because it was never really broken. Anything missing was addressed in 3.5. What you are proposing here, is making 3e into an entirely different game, and removing everything that people liked about it. You have left nothing of the core game with your suggestions, and I honestly think it is far from an improvement.
Now, there are ways to improve on 3.5, but for that you can leave leveling, combat, saves and feats completely untouched:
Removing prestige classes: there have always been balance issues with these. You could leave them out entirely.
Adding lair- and legendary actions: this concept from 5th edition can be pasted right into 3rd edition and make every boss fight objectively better. I suspect many 3e DM's are already doing something similar for decades.
Removing spell components: They are a hassle and keeping track of these has never been fun. It is amusing to see how DDO struggles with them as well, to the point where they might as well remove them entirely.
Remove xp costs for magic item crafting, and always hand out party exp: There is no benefit to pc's being at different levels. It makes balancing encounters a nightmare. So apart from level drain abilities, I would remove anything that disrupts the level balance. Keeping the whole party consistently at the same level, saves a lot of headaches, and promotes the cooperative spirit that the game should be all about.
The Ranger: Even a favorable glance at 3.0's class progression table for the ranger immediately tells you something is off, when you compare it with that of the other classes. I consider the changes that 3.5 made to the ranger the bare minimum to fix the ranger. Not every class needs to be equally powerful, and I would argue that this is one of the aspects that makes 3e fun. But there has to be something to look forward to as you level.
Higher level monster tables: if there is one thing 3e could really use, it would be tables for each monster to more easily raise their challenge rating, and make variants. One of our board members recently started doing this for 5e, (
Link here) and it is a great idea that older editions could also benefit from.
Mass combat/naval combat rules: Ship to ship combat and mass combat in 3e sucks. On the other hand, it sucks in most systems I have seen. Some of the rules for this can be ported over from Pathfinder 1 to fix this.
Firearms: 3e leans strongly into D&D's standard swords and sorcery, but does not take the inclusion of any firearms into account. Firearms can be easily added, but any spells and feats that work specifically with arrows, should also work with bullets for firearms.