True, Comet is indeed simply better version of Cromwell with extra tech & cost.
Not really, it's like saying we should nerf Panther's armor so Sherman can pen more reliably instead of being forced into expensive TD(Jackson).
They both are placed at last tier with expensive cost. They are designed to force enemy to build expensive counter.
Well panthers armour was nerfed considerably, but nobody is complaining about panthers being too good against infantry/at guns & tanks as is with the comet.
A more comparable example would be a heavy all rounder tank like the is2/tiger/pershing which have all had their armour nerfed and are usually slow and lack the utility(self spot/blitz/at gun nade/offensive smoke) the comet has the operate on their own(as well as being limited to 1) thats where it becomes overpowered.
Also there is a theme in coh2 where the counter is generally cheaper than the unit its countering i.e heavy tanks costing 230ish fuel and td's costing 130-145 fuel but the supposed counter to the comet costs more than the unit its being bought to counter and leaves you severely lacking in anti infantry.
The panther should dominate the comet otherwise, which could be implemented with a damage buff to 200 and a pen increase but that would probably screw up the panther vs everything else.