i also thought sunny day wasnt noticable enough and was thinking, in gen3 sunny day shows the bright rays of the sun, perhaps make it flash/flicker a bit
chikorita isle 3 berry forest, cyndaquil isle 1 mt ember totadile isle 2 cape brink, keep squirtle in vermillion, aswell as charm and bulba wherever in kanto they are found would be my suggestion
bigger bases for more furniture(custom furniture too please) also pokemon overworld sprites to free roam base, with option to adjust how often they move to another tile, speed in which they do, and square area they move around in( such as a 9 or 4 tile area, even 1 tile if they are only turning diff directions!