So my three comparison points are, having handled an OHT (gave it to a friend), owning a Rucksack (slidelock) and a Spyderco UKPK drop point.
I think the OHT is a good design to meet it's requirements. I think a true spearpoint like the Rucksak has (or near enough) really does need a lock, its too easy to snag a sharper tip on something and close the blade. A one handed slipjoint is useful, but I think needs to have a couple more design features to assist with that risk, and I think that all the spydie slipits do that pretty well. At the end of the day the OHT is not a specialist tool, it's a generalist that needs to be pretty okay at a lot of different things, and I think it holds that balance well. As for the serrated tip, most people do fine work near the handle, not out at the tip, to avoid accidental prying forces, so it makes sense to me. I'm not a serration fan, but I'd rather those than many other formats. According to SAKwiki, they were available in plain edge from 08 on, so look for model 54875.
Also, keeping in mind the price point it sits at, removing the lock is possible (it is actually a slipjoint with a safety, the liner doesn't contact the tang) But that means changing the rest of the geometry, and I'm not sure if that would mess with the backside layers. That said, if you wanted to do that mod, it's one of the easier layer mods that I can think of.