I'm not sure I can find it in the patch notes now but I noticed I was getting a lot fewer medals for big games at Tier 3 and below and sure enough in the achievements section you now see minimum tier 4 for all epic achievements and service awards. I can see the logic, getting epic achievements where there was only one human opponent late at night was a bit much, but I thought it would have been announced
Added to that there the rewards for the lower tier daily missions are pretty pointless (10k credits when the plane will have made >50k in the battle to achieve it) and there are no tokens at all unless you have a tier 8 (I'm not planning to rush so no likely).
I can see it making Tier 4 a lot busier for the chance of a reward but I still think the daily missions are not worth even worrying about even if you have a few tier 5s there to get a whole 25k!