I dont necessarily think its a 4 piece problem.  I think its a problem that so many sets are outdated. 

Should Plarium remove some sets or offer better sets in place of the old ones?  Dungeons were once a place to harvest gear but now its irrelevant.  

i think only 1 set simply leaves almost nothing to make up a strategy , the game would just be way more interesting with 2 biger sets at once

They have buffed them in the past, but honestly a fair chunk of them could probably just be removed. 

i understand that but woudnt it make the game way more interesting to change the requirement to 3 piece and to not remove  any of what little content this game has?

I don't know that making any of them 3 piece would suddenly make me use them. 

I think the most common use would 6 pc merciless and 3 pc of whatever flavor the champ needs.

Im just trying to think what 4 piece set Id even bother using if it became 3 other than Savage / .  The variable combinations are just too good.

6pc merciless and 3pc lethal to ingnore 60% defense

Double 3pc regen to heal 30%/turn

If they did make 4-pc sets into 3-pc sets though, it'd take about 4 days before people started complaining '3pc sets are too limiting, make them 2-pc"

It would definitely have an impact on certain gear combos. I could see 6 pcs SS with Lethal Combos popping up regularly....but why would Plarium even consider this?

Doubt they ever would.  I still think if anything theyd just rebalance the sets.  

I actually think the design as-is is smart.  Pick your poison, choose your focus for gear, you can't get it all.  I think it works.

Yeah no... why stop at only 3-pieces? You are familiar with the variable sets, aren't you? It should be obvious to point those out seeing that they're the reason behind the other sets being useless. 

Also, the pain point to address here is not just the bonuses being compacted in that very set- it's the convience granted by the respective area you've obtained it from. Feral? Join a OP guild and attend Seige. Merciless? Gather your roster loaded with pre-built toons that you've accumilated through the start of your account, get stronger throughout progression with the cards and trinkets to obtain the loot or the currency needed for the loot at its store. Everything else? Start over from scratch with each and every toon fitting that specific criterea or... you're stuck...

When it comes to acknowledging this, I believe it's better to revamp the older, already- existing content instead of gradually sweeping them under the rug.