The sheer openness of the front system causes problems that really ought to be acknowledged even by people who like it (me, for one). Other mechanics cause problems too.
I'd disagree. It means you need to use different tactics and think about the map somewhat differently; whether that's a problem or not is probably more a case of personal taste. Personally I prefer the frontline system, but I can see why someone who enjoyed the sector based system of Wargame might dislike it.
* Maps have to be smaller as all points must have presence and a certain level of concentration is necessary for entertaining fights
* Maps have to have less design complexity because pushing frontline in wide rivers (ex Nuclear Winter is Coming map in WRD) or big mountains (ex Bloody Ridge in WRD) isn't really possible for some divisions.
I don't think either are necessarily the case. You don't need a presence across the entire map; if we both push our respective left flanks and miss each other all that happens is the front line rotates ninety degrees. Forces have to engage at some point in order to make any difference to the battle. What the frontline system does do is make where that engagement happens dynamic according to the players involved rather than being a 'set' position according to the map, which is no bad thing. This kind of gets into tactical decisions - on some maps, with some divisions, I might post a picket force to cover the flanks; on other maps, with other divisions, I might be better off moving to occupy the centre ground in force.
I don't think it's division capabilities as it is the theatre that's dictating map design. We don't have complex maps because Normandy isn't a complex geography. Maybe if they incorporated other theatres we might see more varied terrain (Italy would provide for the mountains; Netherlands for the rivers).
* Map meta is much harder to create because weird shit is more common. A critical bush or other terrain feature in one game might be totally irrelevant in the next. This creates an enormous learning curve challenge.
It places more emphasis on knowing the division and units you're playing rather than the map. I wouldn't consider that a bad thing. I'd also argue it's an easier learning curve - if you understand how the division you're playing (and your deck) works it's transferable to any map; when it's the map dictating the battle a lot of the nitty gritty of deck management and faction selection is gone in favour of understanding the map instead.
* The scoring system rewards obnoxious play, such as jamming transports on the edge of the map or sneaking fast commanders into the back line.
The same applied to the sector system to be fair. It's less of an issue with the frontline - the victory clock is based on simple area control, so as long as 51% of the battlefield is covered in your colour (whether contigous or not) you're the one winning. Sneaking units around can work, but as above we're getting into tactics here; if we're bogged down in the centre and I haven't covered the flanks sneaking a few units around can work. If I'm beating you back in the centre however about the best you can hope for is it might buy you a few seconds.
* It gives away a lot of information for free that other games make you work for. If your strong force isn't moving the front, it implies enemy is strong there too. If your weak force pushes the front, it means there's nothing there so push for free turf. Much harder to bluff than in other games where a show of force can imply greater strength than exists at a point.
Conversely much easier to lure your opponent into overextending before isolating their probing force, and thanks to the way the surrender mechanics works, much easier to annihilate said force once you've shut down their corridor

It's simply different information, and therefore requires different misinformation to pull off a bluff.
The only real downside I see in that respect is that you can use it to target area attacks with artillery / aircraft. There's still an element of risk since you don't know precisely what you're shooting at (trying to strafe a panzer with machineguns doesn't usually work out so well) but it's still a bit easier than the old "hunt the CV".
The ambiguity and hard points of WRD come a little closer in some respects, but neither is historically accurate in any way shape or form.
It's an abstraction in either case. I think the frontline approach is probably better suited to WWII, particularly the Normandy campaign, than the sector control method (in fact I think it could be argued one of the problems the Allies had was approaching the campaign as a question of occupying strategic goals rather than pushing the line), though neither could be claimed as particularly accurate at the level SD focuses on. I think Close Combat probably presented the best interpretation in regards to historical accuracy, but as you say gameplay should be the first consideration and the CC approach only really works when you have multiple battles on the same map, with each battle affecting the next.