The short version
What separates premium from expensive
Corbett has plenty of properties that charge a premium rate and deliver a mid-range experience with better linen. The genuinely premium ones are distinguishable by a short list of things, and none of them is the bathroom.
The first is land. Seclusion in Corbett is bought by the acre. A property with substantial grounds, mature trees and distance from the main road gives you birdsong at dawn and silence at night; one on a narrow plot beside the road gives you traffic and the neighbouring resort's music, however good the suite is. This is the single biggest differentiator and it is visible on a satellite view before you book.
The second is the naturalist. Corbett assigns an authorised guide to every safari, but a resident naturalist who briefs you the night before, reads the alarm calls, and debriefs afterwards changes what you get from the same three hours. On a drive with no tiger, a good naturalist is the difference between a disappointing morning and a fascinating one.
The third is permit handling. Properties operating at this level file their own permits early and hold vehicles rather than sourcing them. On a peak weekend this is worth considerably more than any facility, because it decides whether you get the zone you wanted.
The fourth is service ratio, which is invisible in photographs and obvious within an hour of arriving. Someone knows your name, the early tea appears without being chased, and the kitchen adapts. That is a staffing cost, and it is most of the difference between a good rate and a high one.
Where the money is worth spending
Spend on the location before the room category. A quiet property in generous grounds with a standard room beats a suite fifty metres from the road, every time.
Spend on a naturalist-led safari if you can only do one or two drives. It raises the floor of the experience much more reliably than upgrading the vehicle.
Spend on a private-pool villa only if you will use it. In December you will not. In May, with a family, it can be the best money on the bill.
Do not spend on a river view you will see twice. If the itinerary is two dawn safaris and two late dinners, the balcony is decorative. Put the difference into an extra shift or a rest house night.
Consider the shoulder months. Rates at the top end move a great deal with season, and October and February often give you the same property and the same forest at a materially better number.