It is getting hard if not impossible to install devices without having to take another device offline. I think there should be 2 or 3 decks per rank point.

adding more deck per point would severly reduce the value of ship real estate. part of what sets GL apart from other games is the ability to Install and Uninstall Modules as your needs change. if everyone were able to always have their best tech equipped in all the categories it would eliminate one of the strategic elements that makes GL unique.
and with ship bots and rescued prisoners from standard artifact draws deck points are potentially infinite if you are patient.
i'm sorry but i feel this idea would do more harm than good to the game

Plus, there is an upper limit on how many decks you need (I think 4500) to have everything installed. You can never have enough of the other options (save cargo).

well said and exactly the point that needed to get across

why not just do so after we get to rank 100 it will be increased because after we get in rank 100 evrything get harder

Difficulty only depends on your personal play style and how well you know the game. If you research energy techs, you'll actually make the game a lot easier, because you'll rank faster and therefore have more rank points to spend. Plus there are several NPC-gained relays and reactors that make it easier to level, not to mention the mission completion rewards.

I personally don't think there is a problem at all and I really don't agree with increasing the rank points per level. As people have said above, the constant need for more deck space makes Galaxy Legion unique and strategic. Just keep playing the game and read the Wiki to get hints and tips.