Hi Shehzad,
This is really tricky, as there can be legitimate reasons to have duplicate content. Your example of Hotel reviews is a good one: Those reviews can be useful to the end user (and help conversions) whether they are unique or not. However, as we all know, Google really isn't a fan of duplicate content.
A lot of people would scream "dupe" and tell you to instantly remove it all. Generally that isn't bad advice, but it's worth some thought first:
I think that the first call is to decide how useful they are if you completely ignore search. Knowing that they are not going to help with rankings do they still warrant a place on that page? If you think (or better still; have tested and know) that they contribute to the business in a meaningful way outside of search then you may well want to keep them. This should be fairly easy to split test I would imagine - you can look for affect on conversions, likelihood that they will return, avg commissions etc.
If you imagine that the duplicate content might actually negatively effect your rankings (we'll come to that), is it now worth keeping it?
If you think that the answer is yes then you need to ensure that there is enough that is unique on your pages that they deserve to rank with or without that duplicate content. Plenty of good sites do contain duplicate content and they don't always have more authority than others using the same. However they will sandwich it between useful new content that deserves to rank anyway.
Getting unique content for 200,000 pages isn't going to be easy, but can be done. However you can prioritise and start building it up working from where it is likely to have the most benefit. I'd imagine user generated content would play a very substantial part unless you have a lot of budget - so start thinking about creative ways to get the public to write for you.