If you like the Koetsu Rosewood sound, another Koetsu would be the safest bet. The Onyx Platinum I've heard, though is not nearly as warm sounding as a Rosewood, so there is a signficant difference within that family.
Still, the Titan would be a much bigger departure from the sound you are getting from the Rosewood (faster, more dynamic, more open on top, but leaner sounding). I own a Titan, and have taken considerable measures to make its sound work in my system. It is VERY sensitive to VTA, it requires mating with the right phono stage, etc. And still, if someone says it is too analytical and cold sounding, I can understand the sentiment.
Outside of the Koetsu family, but, more in line with the warmer sound of the Rosewood than the Lyra Titan, I like the Orpheus. I had a friend's Orpheus in my system for about two weeks and liked its slightly warm (upper bass/lower midrange prominence) presentation. It is not as "fast" and dynamically explosive as the Titan, but, it is no slug either. The other cartridge I have heard, that is somewhat similar sounding (I heard it in a friend's system, not my own) is the Ortofon PW.
I don't know about the top end Grados. These are very warm sounding and harmonically rich (conveys the complex and full bodied sound of bowed string instruments correctly) cartridges, but, for my taste they sound too slow and muddled (somewhat like a blanket has been thrown over the speaker). I actually thought the table was running WAY slow when I heard the Statement.
Allaert makes some terrific sounding cartridges that are also soemwhat warm sounding but reasonably detailed and open on top. Some of these are VERY good, but VERY expensive. Some have really low output that can be problematic. A friend has the top of the line cartridge and it doesn't have enough gain for his Boulder phonostage -- too much noise and a dull sound. I've heard that same cartridge in a dealer system sound fantastic, so it is a matter of compatibility.
It's hard to even guess what someone else will hear, but my guess would be go with another Koetsu or the Orpheus (the Phoenix is cheaper and no slouch either).