Well like i said above, that is ofc a part of a solution but it comes with a disadvantage aswell, since sometimes, inside spawn, is the perfect mg spot.
But its not only about axis heavy classes. Lets take a look at frostbite for example. If you wanna push through the upper spawn towards objective, it would be really effective to just nade the ppl holding there. As an Axis player u have a pretty easy life there without the fear of getting naded or panzered. you just sit there and pre aim that door. If there is like 3 axis holding upper spawn, there is no way to kill them fast enough to push through towards the objectiv afterwards by just using smgs. You might kill all of them, but it takes time, and thx to the short spawntimes, axis will just spawn in your back before you get to the object. So preventing spam kills (nade/rg/pf) on upper axis spawn actually makes it useless to even go for that push. Atleast if axis is actually trying to hold upper spawn and the teams are somewhat even.
Another example is bremen here again. If you wanna push through spawn, you want to just airstrike that area before you push to actually create an opening for that push.
Lost said it already above: You dont allow SK on anytime of the spawncycle, just not a certain amount of seconds (8 for example) after spawn. I just dont really understand why