Why "Dreaming high"?
Because I'm suggesting something that I suppose that isn't easy to implement.
Since Defenders' sets are supposed to focus on defense, the shield should be the most important part of them.
So, i think that could be interesting that, when using a piece of Defender, you starts to select a shield instead of a weapon.
What it means?
When using a piece of Defender, the Next Weapon start to work as Next Shield. The mechanics are reversed: Instead of one shield and multiples weapons, you have one weapon and multiples shields.
I think that this could open a little space to normal weapons, more for defensive position and diversify for more flexible positions.
For example:
1- On RJP, you could use any elemental or normal weapon and equip Grey Owlite and Royal Jelly Shield, or Grey Owlite Shield and Savage Tortoise, etc;
2- You could use a Troika and equip Swiftstrike Buckler and Omega Shell. So you change to SB when being offensive and to OS when being defensive;
3- Use a shield effective to a depth and a Tortodrone shield, because the universe loves tortodrone shields.
So... What's the effect of increasing weapon slots
More spaces for more shields and Tortrodone shields ;)
I think that the idea is basically it. I hope that I forgot nothing.
I really don't know if the idea is bad, but I don't like of keeping the ideas with me.
If this is plausible to code, I could definitely see it working quite well. The case against it is that there are hardly any levels that really require this kind of effort, as most include primarily one type of monster, and shield doesn't make that much of a difference. The reason it could work in spite of this so well is because of all the interesting combinations you could go with for offensive and defensive shields. If OOO were to release this with a "shield redux" type update, then it would work out quite nicely. Imagine having a shield that reflects damage, or blows up when attacked. That could indeed make the game quite interesting.
Assuming that it is plausible to code, that is. I haven't seen the source code, so I really wouldn't know.