The current system is quite solid. It really screens out the baddies on each key. Why take out the timer?
Timer is there for a reason. It’s not necessarily mean rush, rush, rush.
Each Mythic+ key is one notch harder than the last one… higher hp mobs/bosses, and the mobs/bosses hit harder. There’s a timer to check how fast the party to put them down… like a DPS check to make sure the party composition would still need DPS’ers. Do you want 3 Tanks/2 Healers combo? No timer… let them kill everything in 3 hours? Nope, the game should require DPS’ers too.
Also, the timer on current M+ has this mechanics… it gives timer penalties to each death of a party member. The more deaths/the more wipes, the bigger the timer penalty. And most failed groups failed the timer becoz of these wipes (huge timer penalties). Would you feel triumphant if you completed the dungeon with 80 deaths? LOL. The M+ mechanics is solid enough to screen out people not geared/skilled enough and it rewards those who beats the timer… not necessarily fast run but less or zero deaths with adequate DPS.
If you are really looking for a challenge for a 5-man, beat the timer… again with no deaths and with awesome DPS while following the game mechanics… interruptions, dodging fire, dodging front cone, dodging cleave, crowd controls, dispels, stuns,etc. It’s really challenging. It’s really fun. Dont look at the timer, just focus on not dying and kill the mobs before they kill you… LOL. If you think, we are not doing crowd controls on higher keys, you are totally wrong.
At the very highend M+ like M+15 and above, the timer is very short. It would require a very very high DPS to beat it that is sometimes so ridiculously high. What most people do on such scenarios is to skip group of mobs. With Awakened Affix on M+10 and up, group becomes very creative and smart on the route to take. They device a route very efficient and fast with an endgoal of beating the timer.
The problem with most M+ players is that they feel they are entitled to be invited to higher M+ keys when in fact they are incapable of beating it. They have no proof that they deserve high keys. Do you think the veterns started with high io score? Hey, we started from 0 io score… now me comfortably at 1210 io score and still climbing up all on Dungeon Finder.
Improving the io score is easy. Start with the easiest key you could handle… and beat the timer (means no deaths or less deaths becoz of following mechanics… doing interruptions, with sufficient DPS). Then do the same again on the other 11 dungeons. That would give you a base decent io score. Then start doing the next higher key… then do it all over again to the other 11 dungeons. Dont give up. Keep on practicing. Practice makes perfect. If you are a quitter, you would remain a noob.
I didnt start as a Perfect player. I have lots of flaws. There was a time the group hated me becoz I was tunnel visioning on my DPS and not doing interruptions. I accepted my mistakes… moved forward and improve my game. Now I am at M+12 and still climbing.