I've generally found the Flak HT to be very good at suppression and giving quite decent damage. My main problem with it is keeping it alive as it is such a glass canon. Although the smoke ability is very intense, it dosen't prevent the opponent from rushing onto it or just attacking ground throuigh it.
But overall I would agree that the Luchs is probably the more safe investment, and allthough others might disagree I rarely find the ISG to be worth it (As for the searchlight I think everyone agrees that it is useless in 1v1).
Luchs, puma and walking stuka on the other hand will much more often come in handy if you need something to carry you over before the schwere HQ.
It's the overall battlegroup that is flawed, with all unit needing a buff except spotlight (that yes, it is useless in 1vs1)
Isg is the worst artillery ever, any experienced player will never ever move away a garrisoned hmg because if of the ridicolously low splash damage and aoe.
In teamgames you are gonna need something, so people get it, while in 1vs1, where there is no room for trashy useless units you never see battlegroup and isg ever.
Flak ht can't stop infantry reliably, ptrs are still going to force it, it's just a matter of rng deciding when.
Again like isg, it is supposed to be okw support weapon as alternative to the intended horribad raketenwerfer and mg34, yet they are even worse, unreliable and flawed.
It is incredible that a ww1 hmg suppress faster than a 20 mm flak.
55 fuel......