They implemented it only for try to lower the queue times and hear feedback.
Is different from PTR, isn’t something they worked about think for future, was an extreme try, they even said next changes on experimental will not be so extreme(so they have something in future for experimental and isn’t 1-3-2).
Personally i not have opinion about the gamemode itself, because isn’t balanced enough to think of it about a true gamemode.
But mostly because not all the tanks are ready for solo tank and for real even ex off tank become too much strong in solo tank, like zarya.
How i said, it’s hard have an opinion on something isn’t properly ready to be played normally, maybe if developers first make all tanks ready to solo tank, but if they not even give this experiment enough time, i really not understand what they are doing.