As the camo after all is only cosmetic and does not afaik give better camo rate then the many ones we can have for free in other ways i don't see a problem there.
It is probably possible being good enough players and coordinating with other good players in platoon to have it for free, and is also possible to get it paying gold, aka RL money. But is also possible to live without it.
Probably it was a lot worst in the old times when to have a camo, so a real advantage against other players, was only possible spending gold or paying a lot of credits, it was more then 20M to get the 3 camo for a single tank, and for those that are still grinding trough the lines at low-medium tiers credits are the main problem, i remember that i had more then a tank unlocked but no cash to get it at that time.
The old way was somehow a pay to win one, as the players that was willing to spend gold for the camo or the ones that was playing since a long time so had no more credits issues had a real advantage in the PvP modes against the newbies that was not willing to spend real money to get the camo for every not MBT, at now the problem is the fixed cost of the retrofits that then was tier dependent, that make impossible for new players to play with tanks fully retrofitted, if now i sit on over a billion credits and can spend with no problem several millions of credits for a tank that cost, upgrades included, less then a single million i still remember so well how every single credit was so useful when grinding trough the low tiers.
But if only 1% of the players will be able to get a camo, a completely cosmetic thing this days, without paying gold-RL money imo is not an issue at all.
EDIT:
When I go to the AW shop i see that they sell for real money some camo, if they do it probably there are players willing to spend real money for them, and i don't see anything wrong in it as it is not pay to win. So if the raid is a way for those players, that don't care about spending real money on camo, a way to get them in a path that needs also some effort and skill and that probably will let them have the new camo for less money then the ones they buy straight from the shop, supposing that they only re roll some missions and buy few ones, it is an interesting choice for them.
There are also players that like to grind, thing that I personally hate, I have friends that if between a battle path and the next don't have to grind something play a lot less, for them grinding is the main reason and fun of playing, and the Raid seems to be a perfect grind.
As I don't like nor to grind nor to spend RL money for camo i would probably not get it, but I will probably get some useful minor rewards from the Raid, so everyone can be happy for something if the Raid exists.