As far as I see, freebitco is going to establish as a casino and move from faucet industry into this last one, so... I don't know why you judge this situation only from one experience that includes Doge coin and I think freedoge.co.in is a different project and some people don't even know this website. As you see, almost every crypto casino offers altcoins. And personally I can say that there was high demand on it in one famous crypto casino. I think you should do more market research and then make a decision cause only judging from one experience isn't fair, especially if we consider the fact that freebitco had different concept and dogecoin wasn't added on main website, instead it was a dedicated one.
I think the reason why freedoge wasn't working because it was a whole separate website and not just addition to the current website. I know it may sounds like a boring and long experience to just try it and test it, but I feel like if freebitco.in wants to add more coins, first of all it would need to add that on that website and not create a new website for it.
If you want to add litecoin for example, do not make freeliteco.in , just make freebitco.in have litecoin in it. The downfall to this is the fact that you would spend months and months for this, would require countless lines of codes, amazing design changes and in the end maybe that won't work neither, maybe it would be a bad idea, maybe nobody would care about it, but at the end of the day if you could actually make it work, that would be better than another website.