If you want to spice up Gyms... Incentivize it
I've seen vary many ideas that amount to replacing CP with something worse like Levels, or First In.
I've seen many ideas like arbitrary nonsense limits of pokemon in a Gym.
What I havent seen is people come up with incentives for players to use more variety.
For example: What if you made cash out = 1 candy for each family type (not pokemon) in Gyms. Put in your 10th Vaperon, you still only get 1 eevee candy. Put in 10 different pokemon you get 10 candy.
Want less stability in Gym game? Double the Rewards but keep the same cash out value. This will motivate attackers to attack more. Sometimes it's not worth the time to take down that level 10 gym for 10/500 but if it was 20/1000 you would. You can keep the cap the same.
I'll give ya one arbirtary limit idea too.... want more space for people. Put a hard cap on the number of gyms a player can be in. Make it 15. Put in a 16th and your lowest CP comes back to you. (which also opens up a way for trainers to rescue thier pokemon from gyms)
Put some extra rewards on the teams that are behind to have balance the teams.
Incentives = best tool.
Answers
I like what you are touching on.
Max mons in gyms per trainer: 15 (keeping the max 100 coin)
Trainers can only collect for putting in different mons.
meaning trainers can't just collect using 10 dragonites.
I'd prefer not allowing for the lowest cp mon to pop out, when a 16th is put in. This invites shaving of gyms. At mon 16, the little button on the bottom left corner never shows any more.
I like that thought combined with some leveling between attackers and defenders in general. There should be a benefit for having 6 Dragonites at a high level as a trainer but if not as defenders as offensive lawnmowers due to actualy challenging gyms. Otherwise there is little reason to build deep rosters.
Today I put pokemon in gym lvl 2 (10 reward)
Defeat a gym lvl 2 and put a pokemon (20 reward)
Went to other 2 and put a 3rd pokemon in 2 gyms (40 reward)
I have been around 20-25 minutes to prestige a lvl 7 gym, by that time I had 0 reward, all my pokemon were deleted.
I went back to those 2 and attacked. So I finally cashed out 30 coins.. is SO hard to keep mons....
ps: I hopemy mon in lvl 8 (now) gym last 1-3 days max) It is a 1700+ blissey and is in last position.
i think all gyms should have 1 of each type, up too lvl 10. so 1st guy puts in a dragonite and that would mean no more dragon or flying type (max dragonite in a gym would be 2), next guy puts in a snorlax and that would mean no normal and so on, like that. double type would mean the trainer can choose. they can still keep the ranking by cp.
"limit the number of gyms a player can hold" I would limit it to the max number of gyms that you can collect. 10. That would make gyms more dynamic and also would stop spoofers abuse. In my area some people (local spoofers) control so many gyms that there's no room for legit players.
In Ingress there is a classification ladder of the most influential people in an area. I expect something similar to come to PoGo with the rebalance to promote team work and competitive game play
I don't see how that would stop spoofers - there's no incentive AFAICS for a spoofer to hold dozens of gyms (except maybe for safety? or bragging rights?) - they'll just have multiple accounts so each can hold 10+ gyms.
Also, isn't it in Niantic's (financial) interest to allow ppl to hold lots of gyms that they never collect on? Same for inactive accounts? Also makes it look like more ppl are playing then may be the case...
You are over complicating things... I too think limiting people from using the pokemon they want to put in gym is just arbitrary... not only that, it's bad game design. Someone around here suggested that gyms could be specialized, something like... if you put a Fire pokemon in a Fire gym, they get a boost in ATK, or if you put a Grass pokemon in a grass type gym, they get a boost in HP or something like that, that would spice things up, and the other thing I'd suggest is just don't pop pokemon out until the gym goes down completely, maybe have them pop out after x days (if the gym hasn't been brought down before that). Finally, just give people something for attacking gyms, even if the gym doesn't go down completely (maybe candy, maybe stardust), or even a daily bonus for fighting a gym and prestieging a gym.
I agree that incentives are the best way to do things, but things should also remain as simple as possible.