Samit, you can just put a "This domain is for sale" banner so potential buyers know it is for sale.
An end user won't care about the mini site itself 99% of the time (in a positive or negative way), but there are plenty of other benefits that add value such as ranking well in the search engines and increasing traffic. You can't get that with a parked domain, and you rarely get that with mini sites that have scraped content.
Most domainers, when selling to an end user, tell them the exact match domain will help them rank in search engines and get traffic day after day. If instead of selling them on the potential, you can say "The domain is already on the first page of Google and Yahoo for keyword phrases you pay $1 per click for, and gets 2k visitors per month. These are pre-qualified leads looking to buy from you," you're sending a much more powerful message. You don't need to convince them it will work when it's already working.
However, without approaching an end user, will you get more inquiries from a mini site than a parked page? Probably not much, other than when an end users comes across your domain from a search engine and inquires. Some people argue that having a good mini site helps the end user visualize their future site on the domain better, but I don't really subscribe to that theory.
Anyway, just my $0.02.