A very nice roll out for your first COH2 map! The SPLATS will have no negative impact on performance, unless you put more than 5 overlapping. It will really add some shine to the map, too. If not for this one, absolutely plan ahead for them on your next. When done right, SPLATS make the difference, in my opinion, for the maps that have "it". No amount of objects can take the place of them.
A good example, is where the burnt out truck next to the crater, there are some SPLATS "nm_debris/poster*" and "nm_debris/rubble_misc" that when placed around the truck, add to the destruction detail. Also, "Crater_dirt/Crater_vehicle_wreck" beneath the vehicles stain the ground with burned marks.
Regarding the resource sector count, is there a reason you added in the extra fuel and munitions? Double the count can really affect balance, especially with OKW. Also, cut off sectors should be added, for additional strategic concept.
Don't let any of this feedback detour you, it should most certainly be taken positively. You have the process down and that's what counts, and moving forward, it will come much easier each time. If you chose to tweak the map, it has a lot of potential to grab attention, and could always be revisited later down the road if your eager to start your next project.
In regards to your next project, focus on sector layout as top priority, before even opening WorldBuilder. Draw out some idea's on paper, and redo them 3-4 times, with variations, then chose the best one. Once I did that, my maps fell into place so much easier, and the workflow was much faster.
Well Done! Cheers.