Well, for one I'm still interested to know if there is a list somewhere which shows the blast range (and suppression effect range) for the different calibre's.
As to the effectiveness, although my observations have been limited I can tell you now it is probably going to dramatically affect gameplay. And very possibly be way to effective. Looks to me like a 'splash area' of 150 metres across is a bit much for low calibre rounds like 17-pounder HE rounds and 3-inch mortars rounds.
Some events from the scenario I played: one 17-pounder HE round hit and destroyed the jeep aimed at, it immobillised a jeep in an adjacent hex and damaged another one in an adjacent hex. A lucky strike for sure but:
about one third of the 17-pounder HE rounds landing in hexes next to jeeps damaged them in some way (again, rounds landing in the same hex, for example if it missed the target but still landed in the same hex, always failed to do secondary damage to the unit in the SAME hex),
an israeli mech infantry squad which had just dismounted had become pinned (no previous suppression suffered as far as I know and was at ready status prior to the firing) just because a 3-inch mortar round had landed in an adjacent hex.
I can't say that these events are typical for the mechanism as it was a single scenario I played, it's far from a valid test. But from this and the information given on the changes it seems it will be a lot easier to suppress enemy units, not just with arty, but especially with area fire and direct fire.
Whether this is good or bad, more realistic or less realistic, remains to be seen, but I suspect the dynamics of the game will change considerably. Well planned and executed attacks will be far more devastating and effective, 'less well' planned and executed attacks will be far more costly to the attackers and easily countered. And as the AI usually doesn't plan and execute it's attacks very well, gameplay against it may suffer considerably. Just my prediction though,
Narwan
PS there are already some thoughts popping up in my head on 'tricking' or 'abusing' this new dynamic but I'll refrain from posting those here. Wouldn't want people to get the wrong ideas!