- increase JagdTiger speed and lower its front armor value;
Simply make it unable to shoot through buildings/obstacles. Minor front armor decrease would be good, too. It already has the longest range of all tanks, it doesn't also need the best front armor.
- ostheer grenadiers small buff;
I hope not, Grenadiers may lack in early game, but are deadly with vet and mg42.
- riflemen small buff;
Riflemen are more than okay in early game, its the equipment system that needs some love, as you pointed out.
- do something about the Tiger. It's a little UP now;
Definitely not in 1v1.
You may be right about the rest.