This concept is perfect. It give the co op that so many of us asked for, while also providing some nice natural ways for the lesser players to still have fun & score.
I am always in favor of smaller maps, as it gives more meaning to controlling territory. In a large map the question is not how to secure a given bit of score, but to spread as wide as possible and avoid all combat. The cost/benefit of fighting for what you know vs just spreading in the other direction is too far towards 'just spread'. In a large map, fighting just means both you and your sparring partner drop in the rankings, so you avoid fights. In a small map, everyone has to fight, and you have to figure out how to fight well. A good economic bot should get you in the top 100. Your combat code should determine top 10.
A smaller map benefits smaller players. In a large map, a top-10 player is only able to indirectly compete on the leaderboard by exerting total dominance over their holdings to maximize gains. They must maximize these gains better than their other top-10 counterparts, as that is the only path to victory. However, if portals and map size make them neighbors with their true competitors, then they can compete via directly fighting over rooms and score.
Finally, I think that when you allow lower players to score, even if they get wiped often, they will still enjoy the season. This mechanic will give them the option to be taken under the wing of a bigger player if they want a higher degree of safety. Even if you think a larger map makes smaller players not in an alliance less likely to get wiped, it's not necessary.
Also, an increased amount of score spawning will make it rapidly apparent that you need access to as many symbols as possible to be competitive. Alliances of larger players can hope to negotiate amongst themselves who places how high and wipe all the small players near them, but that won't remotely cut those players off from spawning elsewhere near more amenable players, which is all that matters. Seeing the wipes of this season, and thinking it apply under this new mechanic, is at best misguided. The incentive structure is completely different.