Are you saying larger field sizes will do the job instead of internet mode when it comes to evosims? Several sims connected with different settings could otherwise prevent stagnation. ...maybe.
IMHO, most sim settings we have today do not really help create environmental diversity and niches. Changing the coefficient of friction or y axis gravity or whatever from sim to sim in internet mode or from place to place in a single sim doesn't really do much to encourage organism diversity IMHO. Not really. Bot's can't really see or anticipate these settings and the transitions between them are not smooth. Generally a bot is either adpated to it an environment or it isn't. Deep oceans and tall peaks are nice, but the interesting stuff happens where you have grandual gradients between environments or even better, lots of different niches int eh same environment Savannahs that meld into forests, coast lines and tide pools and swamps. Once in a while the founder effect is important but in general, fish don't compete with mountain goats and thus you don't see organisms from radically different sim conditions survive generally when teleported into other sims in internet mode with radically different sim settings.
I like using shapes for creating environmental diversity because they create the ability for multipel niches in the same environment. The simple fact of having a shape or two in your sim means that those bots which can distinguish visually between bots and shapes have an advantage if they hang out near a shape. They can hide in plain sight, using the existance of the shape to confuse a preditor. Suddenly you have two niches - the roam the open plains niche and the hide aroudn shapes niuche. They can prey on non-shape aware bots even if they are smaller and inferior while the non-shape aware bots are busy wasting nrg shooting at a wall. Put a few shapes together and you have physical spaces that can be defended, places to hide, ambush from, places where large bots can't follow or long range eye sight is a disadvantage and so on. A bot that knows what a shape corner is and how to navigate a quick turn around it can use it to it's advantage to excape an agressor or ambush prey. Bots can actually hide in shape walls, continually burrowing into the shape, effectively making them invisible. They can peak out every N cycles to see if there is prey in sight or the preditor is gone. Add few shapes and suddenly you have dozens of possible niches.
IMHO, environmental diversity is about providing the means for bots to adopt different strategies that work in proximity to other bots with other strategies in the same environment. You need the physcial artifacts like shapes for this but you also need the geographic space for popualtions to remain isloated for a while so that those strategies can evolve in the first place. And you if have radically different environments with different physical rules, you need gradual gradients between them. Both larger fields AND internet mode (combined with shapes) allow all this, but not because they support different sim settings and differenet, seperate environments. They allow this because they provide population isolation and niche richness of a single environment.