If you aren't using the radio menu, the drogue won't be released and their lights won't come on. I've been doing night AAR without any problems and it's as easy as day time.
Something I think would not only be huge for immersion but is necessary is an LSO. There's not much to be said other than that. The only real example I can think of in another sim is a third party program called vLSO. I think most would appreciate something like that as part of DCS. Maybe even have an option to individually turn it on and off.
Except that's way over the max speed that an S3 will be flying when refueling. I'll have to get with Vidar again but IIRC +/- 250 was the max when he was actually flying S3's.