If the TV has USB ports then you could attach a wireless keyboard and mouse to the TV. That’s what I did, picked up a little logitech unit that’s about the size of a laptop keyboard for $30 and now most (sadly not all the apps on my TV like it) searched I can do by keyboard. Of course I hardly use it, because once you get the hang of it the remote navigating through that letter field is easy, yeah it’s not as fast but you’re never doing more than a dozen characters anyway. Surely not difficult enough to make solving it the “killer app”, especially since I already solved it for cheaper.
I doubt if Roku is cheaper but the wireless keyboard is a nice add-on. Don’t forget, almost everyone has an iPhone or equivalent these days.
BTW, I expect a Roku version of the Chromecast to emerge if it hasn’t already. Roku and perhaps Apple TV are the big players in this market and they are not going to rollover and let Google walk away with their business.