Megaman 7 came out in 1995 after Megaman X2.
Bass doesn't act firendly if you lose to him in the Intro stage, only if you damage him enough does he praise you otherwise he thinks your weak.
Specifically Shade Mans stage is where you find Bass injured. He not only destroys lights lap but takes the original Adapter parts.
Wily also breaks into the robot museum to steal a gutsman model to use remake as a boss in his castle later on.
Before you can fight Protoman you have to find the two other locations where he gives you hints. Then you fight him and get his shield, which only works when standing still. Also only works when the shield is in front.
X doesn't really have a rival. Unless you mean Zero, which isn't really the same thing as Bass.
One thing you skimmed over is that they brought the shops from Megaman IV and V(not 4 and 5) which allowed you to purchases items and powerups, like beat, and enhancements. Of course, there are more, but you have to find Auto's missing super bolt to get him working. Not only do you get more stuff, but you don't have to wait as long for the item to finish.
You mention interactivity with the environment but didn't expand. Some examples include using Freeze mans weapon in Junk mans stage to freeze the lava, or whatever it is, or freezing the fire canons in Turbo mans stage. Turbo Mans weapon can burn down trees in the forest, Cloud mans weapon can power up machinery, etc.
Along with the RUSH adapter finding the 4 letter to activate it, you also have a few other Rush power ups like coil again, and search, which is used to find secret parts.
You can also charge a "few" weapons in this game.
One nice feature they brought back from V and X, is that you can go to other levels during like say stage 2 of wily castle, then go back and still be at stage 2 and not start over.
Also the second time you fight Bass, he used the other adapter.