Please make Archon debuff start counting when getting Archon buff not after Archon buff dissapears.

Archon buff is extremely underwhelming. Investing into recovery period is also very underwhelming when you still have to wait those 15 seconds anyway. If you made it start while you have the buff it would feel a lot more smooth.

How is it "extremly underhelming"?
For a 5 points investment you get +32% elemental damage, +32% energy shield recovery rate and unlock the archon. You can activate it whenever you want via convalescence. Alternatively you can take the mana-spending variant.
It gives 100% shock chance, 100% freeze chance, 100% ignite chance and 25% MORE damage, which is significantly better than increased damage, since its a damage multiplier and not merely additive.
Sounds pretty good to me.

If the recovery period would start counting when you get the archon buff and not when it runs out, there would be no archon downtime. The entire point of archon gameplaywise is that its not a permanent buff, but there is a archon phase were you feel stronger and a non-archon phase where you don't.