Firstly, I advocate for toning down veteracy bonuses, not remove it. But the current modifiers are simply crazily high, and the adverse effects are very significant (fx volks blobs and heavy tanks)
Just because they are to high for Volks doesn't mean they are too high in general! If we include the Vet of Ober this would be two units in the entire game.
Even if we say the Vet 5 of OKW is broken it would be one faction out of four. Even in this case the conclusion is not that vet as such is broken but one faction is.
Secondly, you overestimate the significance of veterancy for the CoH gameplay. It's actually one of the least important mechanics. The most important are squads, cover, garrisoning, light arms ineffective vs. tanks etc. Vet is very low on that list.
Actually no. You underestimate it. Unit preservation and scaling by vet is a fundamental part of the concept of CoH. The basic idea is that a Vet2 unit performs as well as two Vet0 units of the same type.
Because of the fixed pop cap this is somewhat watered down but this means if you keep your units alive and vet them up you field a veteran force wich is twice as strong as a freshly build one of the same size.
If vet is toned down there is not need to preserve troops anymore. Suicide attacks become a basic strategy and its mostly about outproducing the opposition. It also means its possible to pump out T1 as long as desired and needed to then let them all die and replace them with new high tier units. No need to micro individual units to keep them alive. Wich would be more or less exactly as in most other RTS games.
Another reason why vet currently means too much and should be toned down. Because vet gives so huge bonuses, it is devastating to lose a vetted squad to RNG.
Again you draw the wrong conclusion. Not the vet needs to be turned down but the randomness. For example it could be a good idea to reduce the AOE of several of the late game units and focus on their specific task. Why for example does a Jagttiger fire HE shells as standard. Its a dedicated AT vehicle. Make it fire AP shells will allmost no splash as standard and HE as an ability wich needs to be activated for one shot and has a cooldown. Same with the ISU. This would make them vulnurable to infantry assaults and incapable of locking down sections of the map completly. They still will do that to vehicles but not to infantry. They also would stop to one shot AT guns wich at least in theory are their hardcounter.
Vet is simply a major source of late game problems including volk shreck blobs.
This is exactly ONE problem. With one faction and one specific unit.
If vet would be to strong in general it would be true for all factions T1 units. How many Vet3 Conscript, Rifle or Grenadier blobs dominate the game?
For most faction even doctrine, call in, elite infantry can't dominate on their own regardless if Vet3 or not.
Vet bonuses need to be toned down and normalized across factions. God damn, it would improve the game a lot with little consequences.
The consequence would be a boring game and mirror factions. If you want that there are plenty of games out there that do that.
The Vet bonuses should be picked so it makes the unit better in its role, maybe broaden its role and fits the faction. Not global for all. This would create lots of scaling problems. A accuracy bonus for example would be much more powerfull the higher the effective ROF of a unit. Wich means the US would profit most (large squads, fast firing rifles) and the OH least (small squads, slow firing rifles). This is just one example.
In CoH1 the Vet bonuses differed from unit to unit and from faction to faction. In general the US forces improved their ability to do damage plus speed for vehicles and the WH improved toughness. PE could pick each level (offense or defense) depending on unit one made more sense than the other. Brits improved across the board but less in each specific field.
This worked extremly well. Vet5 is rather new. So of course there a teething problems with its scaling.