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A VTT is a huge undertaking in terms of coding, especially if you want to provide it with the features that are expected of a modern VTT; there are some very powerful VTT programs currently out there - enough that I would argue that the market, as it were, is fairly saturated.
I agree that VTTs are a huge undertaking (as I'm developing a type of one myself... Live Gaming). I don't agree that the market is saturated—the market is saturated with the apps that allow you to play RPGs online... but there really aren't many apps that actually make it easier for you to play RPGs, for example.
Take a good look at Fantasy Grounds (RPG-specific programming) and Roll20(RPG-agnostic) and RPGWithMe(play-by-post), for starters. If the features you want aren't in any of those, then think about creating a VTT, and realize that you will have to contend with a lot of RPGers who will say it's already been done before simply because there are a lot of VTTs.
As for tech, web programming isn't a bad way to go. There are a lot of advantages for a web-based app for your users—for instance, saving the character on a website means they can access it on any computer or device—and also for you: people have created tons of libraries. That mean you don't have to program from the ground up, because people have done a lot of the basic programming for you. People have already programmed how to interact with the database (SQL, and others like MongoDB), how to make the server do what you want (PHP, or Python, or Ruby, or Node.js, etc), how to create a visual template from Data (PHP, Django, Backbone.js), and how to display that data (HTML, CSS, JavaScript w/ JQuery).
As I said before, the advantage of using these systems is that people have created libraries (like Node.js, Backbone.js, and Jquery for JavaScript) that will already do a lot of what you want, so you don't have to program from scratch. The down side is wrapping your head around 4-5+ layers of code (database, server, templates, html, styles).