Anything that brings variety and doesn't break immersion or ballance, is automatic 'yes' for me.
In case of doubts, WG can always try 'test' season first, before going full in.
Everyone would have to sacrifice something in order to accomodate T10. Total number of ships per side could've been flexible to address it.
You could've just had few higher tier ships or larger number of lower tiers. Even consumables could count toward total number of points spent as well as Premium ships requiring more points.
It definitely would make things way more complicated and for average player too difficult to comprehend, but would lead to large number of fun encounters.
True, though any competitive gameplay on high enough level requires lot of coordination and analysis.. Hence different leagues. Those better at it just advance further.