Seeing as I am fairly useless when it comes to anything involving editing in OFP except cpp and islands, I thought I'd make a few requests which require new models...
1. A jetski, could be made ship class to allow it to go fast, shouldn't be all that hard once the model is made and skinned.
2. ATV's(All Terrain Vehicles) such as quads and dirt bikes. The motorcycle that came with resistance is pretty fun, but I'd like to see other things like it, such as the snowmobile which came out a little while ago at ofp.info. They would be especially useful for insertion to remote bases where air support/insertion would not be feasible or too risky.
3. McDonalds. I find it quite unrealistic that NONE of the towns on ANY of the islands I've seen have any McDonalds. I live in the back asswards city of Tianjin in China, and they've got McDonalds all over the place.
4. Realistic artillery. It's not that hard. Have it shoot Grenades with a very high init speed and the gun move really slowly.
5. MORE EASTERN UNITS. 'nuff said.
6. Sea planes. Don't know if it is currently possible in OFP, but it would be great.
7. Tall buildings. Doesn't have to be enterable, to minimise lag. A variety of them would be awesome for making a nice city Which I would personally like to do on my own islands.
8. on/off ramps and elevated highways. Again, useful for cities.
That's all I can think of for now.