Wow, thank you so much for taking the time to write this! We really appreciate it
Regarding the first point for the Fields system, it is something that I also noticed during development - getting a new field makes your other fields smaller, which can naturally be a disadvantage. Couple that with the fact that some Passive upgrades are really strong, and you can be discouraged at times from grabbing more Fields. That is maybe, hopefully, the kind of thing that automatically gets fixed by us simply designing a lot more fields with more variety and that synergize with your on-going build; for example, in the run you described, the Fields that provide you buffs (such as Damage Buff fields and Crit Buff fields) could be great additions, but it does come with the downside of making it harder for you to access your main damage dealer, which would be the three light shots, but hopefully we could design and balance the game and the fields in such a way that this feels like a good and fun trade-off. I felt like the Poison archetype was headed in a good direction in this regard, as different Fields had good synergy with each other.
That being said! We did talk about a system to explore and have more customizability for your wheel. We are not sure if it would be a good addition to the game and did not have time to experiment with it, but it would tackle this specific thing. Basically upgrades that gives you more avenues to customize your wheel. For example, an upgrade that lets you increase or decrease the size of a field. This could be integrated into the current system (just another type of upgrade that can show up), or even a parallel system (eg a vendor between bosses). So maybe now, you would chose upgrades to ensure that your three light shots is your bread and butter, and remains as the biggest field in your wheel, but you can place other, more supportive and/or niche fields in your wheel, and have them take up significantly less space. For stuff like situational fields and such, it could be nice!
Again, really appreciate your feedback, thank you so much!