You are correct on the licensing. Most applications require one license per instance of a software product as opposed to requiring a license for each user that will ever use the product. In the case of Microsoft Office, you do not need to purchase a license for each user's computer as they will not be running it from their local machine. You will only need to purchase licensing for the maximum number of concurrent (l)users that will run the software from the MetaFrame server.
Other advantages include configuration control (just one copy of the software to configure), upgrade control (again...one copy to upgrade - not thousands), ease of support (you control what's on the server), and ease of remote support as you can take over the (l)user's session and help them through difficult things like changing font sizes...
Also, MetaFrame is scalable as you can add multiple servers to a farm and configure one server as the "master" install and cause it to push it's configs to the others.
MetaFrame is really rather spiff-nifty. About the only downside to deploying a MetaFrame farm is that the upfront hardware costs and ongoing server administration sometimes causes those with purchase authority to gasp on their own breath. This is not a downside to the product itself, but more of a downside to having that person be in charge of purchase decisions.
If I were you, I'd continue to pitch the web-enabled deployment dealy for enterprise-level appllications such as AP, AR, ERP, CRM, etc. and offer MetaFrame as the backend solution for productivity applications such as Office, Email, and other legacy applications that can't or won't be migrated to the web. In keeping with your web-enabled vision, you may want to pitch Citrix's nFuse product which is essentially an add-on to MetaFrame that allows you to deploy your MetaFrame applications via a web browser.
Don't forget that MetaFrame allows to to publish either an entire desktop session or just individual applications. This knowledge could come in handy in your design. For example, if you are indeed looking to promote a web-enabled (l)user experience, you may not want to allow them to have an entire desktop session and just kick out each application seperately so that you can control their working environment and experience.