I think it needs to keep both, to be clear (some sites ONLY have you choose from that drop down menu)-hitting enter and being able to advanced search is super important since some shows (take Midnight Diner and all the Boys Over Flowers versions as the first things that popped into my head) have many versions of it or seasons etc... or "Hero" ends up being an annoyingly common title, too, stretching back to the 60s or 70s (though I'm not sure the oldest of "Hero" named kdramas is on here)...
Since MDL suggestions are implemented largely based on how easy to implement them they are, a note for admins: Rather than copying Viki on coding, one practical thing they can do is simply adapt the coding MDL already uses for adding titles to lists and adding cast or crew members to a title-perhaps after the first 5 or 10 titles, it can have a "show more" or "Advanced Search" option to hit the regular search. When you go down to add a cast/crew member to a title, it gives you a pull down (and if the name is common or parts of it combine in many people on here, it will scroll to more-even some irrelevant in that case bc of all the alt spellings of parts of names). THAT function actually needs a show more kind of option because fairly often a title won't show up in the most common ones and on voting lists that aren't on your account and for cast members, you just can't do a "show more" or anything of the sort, so it sometimes makes you have to figure out a cast member, hope it's on their page, and go to the cast just to get to that title (or to add the cast that doesn't pop up, you'll have to edit the cast/crew member's page, not the drama page, which is REALLY tedious to me).
Pointing this out simply because this kind of search has, for MDL's database at least, a limitation partly caused by the sheer number of titles and people in it so unless you're searching for one of the most popular or trending titles, you'll oftentimes not have it in the top 5, especially if looking up one of the English titles that is used where it streams but is not the main title on MDL. It's a caveat and supplemental info for the suggestion, not a counter against it. :)