Indeed, the AOI and other documentation allow for some leeway and things are less regulated than on other fields. So allow me to approach this question from a practical standpoint.
Here´s a summary from my last few visits to FRA.
- In general, ATC works quite well and efficiently; there is no need to overthink it. Playing along is sufficient.
- Expect speed control already during descent, usually to the tune of 290/270 knots "or more" / "or less" depending on the controllers intended sequencing.
- Plan for the STAR and (long) transition initially, note the altitude restrictions: expect to be cleared accordingly and plan Your descent so You can achieve them when cleared. This will keep You within an altitude range allowing for shortcuts as well.
- In low traffic periods, expect to be taken off the arrival and turned into a base leg rather early. In higher traffic situations, there may be some transition flying involved. I have not flown holdings in FRA for some years, the last ones were involving nasty weather situations.
- Rate restrictions on arrival and base are to be planned for, something like 2000fpm or more. Expect to be at 4000 or 5000ft (depending on planned approach) for quite a while.
- Intermediate approaches to parallel runways are staggered: one side will intercept the glide out of 4000ft, one out of 5000ft.
- Runway assignment is done quite late, often when You are on base. If traffic allows, You may be offered a choice of left or right.
- Runway 07L/25R comes with a steeper G/A gradient requirement: 4.3° to 4130 on 25R, 4.1 to 4100 on 25L. If Your performance calculations say You cannot accept this, request 07R/25L, it will be given without discussions.
- Expect 220kts until shortly before glide slope intercept, then 170 until 5.
- The center runway is for departures. On occasion, a visual swingover from the southern runway will be offered. LH are usually quite keen on this, but a "no" is a perfectly valid answer and will be accepted without discussions.
- After landing on 25L/07R, before crossing 25C/07C, expect to taxi on M quite far down to the departure end, then be held at the CATII holding point (also in CAVOK) to wait for the crossing clearance.
- On ground, expect to be handed over between ground controllers surprisingly often. You will be cleared down one of the long taxiways to hold short of some intersection, then sent to the next frequency. This is usually seamless and does not cause many stops.
- Be warned: Ground vehicle traffic is dense and there are many taxiways crossing vehicle lanes. Ground vehicles are to give way to aircraft - in theory. Be ready to brake and stop when needed. Not always do they anticipate Your turn into a lane and stop, sometimes they will try to quickly cross in front of You.