After considering this for a while, I am in the process of changing my pricing guide based on use and exposure that the images will receive, and I have started to explain it like that to my clients. Although I have always operated a rights managed model, I feel this is the most profitable and fairest for your clients, as long as you can explain it in a way your clients can understand. With that said, I am still basing my estimates for architect/designers on the time it takes to create the images (mainly because all architects use the images in the same way) but adjusting my fee based on the location of the firm, which will have an impact on exposure. I also have created a social media "add-on" package for designers with prices based on the size of the firm. Firm size plays a role here because the larger the firm the more contributors to their social media outlets (in maybe more outlets) resulting in larger exposure.
For hospitalities I completely agree with Ashley on how to price, by the image and exposure received, not on time taken to create it or the amount of professionals needed. It is more of a gamble, especially if you use others besides your assistant and will eat away at your profit, but if by using other professionals and the time it takes you increase the value of the images to your client, they would be more likely to increase the range of licensing they want resulting in a larger profit for you. Also, it is fairer to your clients because you can now take their budget and type of business in account when creating the estimate; you just need to explain it to your client in a way they can understand. And of course the only way to get to work is by creating extremely valuable images that your clients will want to use.
Also, I am trying to come up with a non-threatening way of explaining to clients that the usable life of an image is not that long if you are serious about your marketing, which is true. Architects/designers are naturally aware of this and put it into action whether they realize it or not by having their latest projects at the foreground in their marketing. Because of this, and once again consistency, I am not putting a timeline for architects even though there is one. For hospitality I think the usable life would be 7/8 years before the establishment would need to start rethinking there marketing so as to stay current with the times and tastes. But others may be shorter, so time constraints here are necessary in order to be fair; you should not charge you client for 8 years if they only need the images for 3, which should be explained in a way that make sense.
Once again these are my thoughts I came to and am not totally sure if it is the best. At this time though it seems the best and most fair to me.