The long and the short of it - infantry combat needs re-evaluation.
1. Infantry can take ground too effectively without support.
2. Suppression to infantry squads on the move is not effective enough.
3. High availability and cheap cost makes them ideal for both holding and taking ground because of the above problems.
Possible Solutions -
Infantry that takes any kind of fire out of cover should have more of a speed reduction. This would occur when fire is taken, to simulate them hitting the deck and crawling or crouch running. This would be in addition to the more drastic "suppressed".
Infantry availability is reduced across the board and/or the cost of infantry is increased.
Time to suppress is decreased drastically when out of cover.
Recon spotters are substantially buffed to allow them to spot sooner.
Ranked Play and Meta -
Currently combined arms is not favored because of the above factors. Currently the meta revolves around throwing as many infantry at the front line at the expense of tactical play.
This brings me to my next point- the Flag system as a victory condition is not working.
1. Less organic, favors static play. Infantry is naturally favored with this victory condition.
2. Static flag points make maps play the same way every time.
3. Breakthroughs and encirclement matters little. There's little incentive to push beyond the static flags.
The problems with infantry are tied to the problems with the flag victory condition. For the benefit of tactical play, moving back to the SD44 territory system could possibly remedy some of the problems we're seeing and bring back fluid, tactical play.