I look forward to the exaggerated complaint posts in a couple of game months, when lots of people open up their first base airport. It's communism if it ends up with some actual fair, long term competition? Yeah right.
Think this change will really hurt those attempting to run regional airlines, those who let things run for a week and then schedule in bulk when they get a few free hours, etc. Might make the default playstyle of grabbing every slot possible whenever a new set appear not work anywhere near as well, but I think there'll be some serious unintended consequences.
Slot hogging is one who uses aircraft too small for the route. The new system does not make this determination. It indiscriminately punishes larger airlines.
I would say the exact opposite. Slot hogging is making a conscious effort to buy as many slots as possible, to limit your direct competition to as few slots as possible. Using smaller aircraft out of an airport that is not going to be persistently slot-locked requires buying a lot of slots at once, up to 105 for 3 turboprops, is certainly not slot hogging, but the new system will not make an allowance for that. It is smaller airlines, short haul airlines, in size 5 but not slot-locked airports that will be indiscriminately punished.
It is going to be longhaul airlines, starting in big airports, that will be punished the least, because they get the most revenue for the least number of slots. Exactly the same way that starting with 2 x DC10 as your initial planes is the best way, by far, to start growing explosively. 35 weekly slots is enough for 7 LH planes, or 2-3 a320s, or just 1 turboprop. Limiting explosive growth at the start of the world is something I'm 100% in favour of. But doing it this way is going to offer huge advantages to LH over regional, even more than it does now. They can get 7 times as many planes before running into highly inflated slot costs. And each of those 7 planes will produce much more revenue.
Make slots be plane-size specific when purchased, and not transferrable, and it'd work far, far better. That way, the 'bought too many slots in last month' amount could be weighted differently for each size, say small = 0.5, medium = 1, large = 2.5, v.large = 5. Go over 200 points in the last month, and you're paying the anti slot-hog fee. Allow a bank for those who are not buying slots, that credits them with 50 slots/week multiplied by the % amount of slots in their HQ between 0600-2255, less 20. So in an 80+% full airport, e.g. LHR, CDG, AMS, etc, you get no credit. In a 50% full airport, you'll get 15 slots/week added to your bank, enabling you to schedule in bulk later. In a near empty, 20% full airport, you'll get 30 slots/week banked, so if you go 3 months without a slot purchase, you'll have ~600 slots available before hitting the hog-fee, enough for 15-20 turboprops.
That would slow down explosive growth, without unduly punishing those running regional airlines, without unduly punishing those in bigger HQs without so much slot pressure who want to schedule in bulk on a weekend.
It would also stop players abusing the current system by getting a handful of LH planes as cash cows, then any 50-100 seater they can find to hold as many slots as possible for later switching to LH. You want to hold a slot for a v.large LH plane, you'll need to buy it as a v.large slot from the start. Or buy it as a medium slot for a medium plane, then close the route and rebuy it as a v.large later on. Easy to slow that hogging down too though, if you give back a slot of one size and want to buy it again, you could have to pay a really large fee.
Players attempting to run huge airlines in huge airports might actually have to start focusing on actually buying slots for the routes they're about to fly, instead of focusing on greediliy grabbing as much of the limited resource as they possibly can, in order to keep anyone else from having it, and to distribute to their real routes at leisure.