There are many problems with a totally open gameplay.
Nope. There isn't.
You have yet to provide evidence or even argument of even one problem.
It has been found out from past experiences, and I strongly suggest you take these experiences in account. No one is a master gameplay designer at birth (despite what some people seem to think about themselves) and it is good to listen to the advice of people who have seen many maps succeed and fail. If you don't trust my word, play a few games on the England map, and ask MrBenn, the maker of the map, what he considers the biggest failing of that map.
Just because you and MrBenn and a few of your lapdogs think that the map isn't fun, doesn't mean that other people feel like you. There are plenty of room for niche maps, and the 'classic' gameplay maps have a huge following.
Also, I must add that I find it odd that people like Helix can disregard the experiences of Doodle Earth when making the Cairo map, while people like feyerv must by all means take heed of every little failing of every conceivable map ever made. Did someone say nepotism?
With a totally open gameplay, you don't encourage offensiveness, you will simply grant the victory to whoever manages to get the best dice/drop and grab the largest swath of land.
First, I didn't realize we were required to encourage offensiveness. Care to elaborate?
Second, it's not as clear-cut as 'simply granting the victory to the best drop/dice' - quite the contrary in fact. With many paths of attack, you'll have to think hard on where to focus your forces. Indeed, there's a lot more strategic choices involved here. You have to decide where to place your armies over several territories, not just the 2 or 3 that makes out your bottlenecks.
Thirdly, people are normally awarded the victory if they manage to grab the 'largest swath of land', yes?
Even the classic map has impassables - the oceans. Ever wonder why? Why didn't they just let all land areas assault other nearby land areas oversea? Constricting the gameplay somewhat, providing various assault routes, but not allowing every place to assault every other place, creates more opportunities for strategic play.
This map wouldn't allow 'every place to assault every other place'. The oceans are simply a means to create the 'outer rim' of a map that isn't circular. For example, it's impossible to attack from Transilvania to Drobogea.
You might come close to a point if we were discussing my Constantinopolis map, but that has other gameplay elements to enhance strategic choices.
I'm not saying you should choke the map with too many impassables. Don't think extremes here. I'm saying that you should seek the balance between totally open and too constrained gameplay. A balance where there's an ample amount of assault routes and various possibilities for a player to expand, but not a too open, go-berserk-free-for-all-battlefield...
I haven't played on the England map (yet), but I'm sure there haven't been many 'go-berserk-free-for-all' games on this map. Quite the contrary, I imagine this map is quite slow to develop, with players being very careful what to attack and defend.
Yeah, I guess I never give any advice to new mapmakers or anything. It's not like I spend hours writing tutorials for them or anything. It's not like I comment on each and every new map thread or anything.
Well, you do post in many newcomer's threads. It's just that the quality and tone of those comments are often so poor that you would do better not to post them at all.
I went looking for such a post I remember, and while I didn't find that exact post, I happened upon a treasure-trove of condescending, dismissive and snide remarks:
cauliflowerswishful thinkingNo more luckTaking place hereOh, and your advice is not bad because I disagree with, your advice is bad entirely on it's own merits.
Prove it.
At the very least, argue it.
But please do so somewhere else. This isn't the right place for you to vent frustrations or compensating for personal shortcomings.