For me, its the fundamentals of realism that matter, the weakest part of this in current verions that needs the largets overhaul is by far the ai system.Thing with the ai is....its reasonable, but by no means great. In todays world of computing there is no real reason why the following could not be done.1. Improved intelligence on runway exit speeds and use of taxiways for this.2. Improved intelligence on 'line up and wait' operations on single use runways.3. Have planes fly in airways once at cruising altitude, harder and may require more computing time in to a database on loadup, but once running is unlikely to be any more difficult to control than the original method (point to point).4. Have an updatable list of navaids etc.5. I really think there should be the option to put in SIDS and STARS, holding patterns and final approach procedures in to the sim for each airport. Now the real crux of this should then for the sim to recognise, or allow you to set which airport 'professional procedures' should be followed for by the ai. That way, the computing and processing power can be just directed to the selected airports. E.g6. On loading, restrict the time it pre-loads planes meant to have departed to within 5 minutes. 7. Have ai properly seperate using speed variations.Say you have a full ai sim. In the new version id imagine you could have the professional procedures and holds etc built in for egkk, egll, egss etc etc (All london airports even). However, as your flying in to or out of heathrow (or even spotting at one airport) you tell the sim to use real-world professional procedures at say, egll but tell the sim to use 'standard ai rules (much like the ones in fs2004) for all the other airports....your not there to see the mess ups caused by the ai system at those airports. Again, this would be something you have to probably set before your flight sim loads the flight.I really dont think that is too much to ask and would add a considerable amount of realism...but not total sim-wide realism, this could occur on the hardest settings etc, but is something that from a programming point of view would not be horrendously difficult (imo), particularly if a built in add on program can be included which allows users to input specific airport data. Many have also said improved weather and clouds...agree with this.Thats my few cents worth and I hope if anyone does read this from MS flight, they can take note.