I was thinking of potentially swapping Crew Repairs for a Combined Arms type of assault ability that would add some late game power to the doctrine but comes with some requirements to use to its full potential, instead of adding another no-brainer click-and-forget ability (skill planes). Designate Command Vehicle ability could work too.
Sould get away from a unit based ability.
For example Lend Lease is already 4/5 units for slots and one ability to support those units. It allows the brits to play in a way simular to USF obiously with CQC, mortar, and M10
You don't have to make every doctrine viable in the late game. It's okay to let Lend Lease be a very strong early and mid game doctrine. It's plenty viable for its early game alone but Assault sections are a bit too strong making this very much a cheese doctrine. Everyone wants every doctrine to be strong in every stage of the game now a days and it is making every commander feel samey.
Command Vehicle is very underutilized due to its negative pentalties to parent vehicle. I sugges reducing some of the mobility pentalities.