I've got a Trek 520 that has straight bars with bar ends.
I tried the drop handlebars for several months. I found that I had two-and-a-half positions: Hoods and tops of the handlebars, with some variations in hand placement on the top. If I'm out touring, which for me means riding along at an easy pace while looking at the scenery, I'm not going to be on the drops.
In spite of the handlebars being at seat height, and having two layers of cushioned tape, I was just not comfortable on the drop handlebars. This had been my experience with other drop handlebar bikes.
I then had the flat handlebars and bar ends installed (change of shifters and brake levers, too). It was immediately better and was similar to my experience in using MTBs. I then improved it by adding a softer handgrip to both the bar and over the bar ends. Much better. Rides of 50-100 miles were no longer resulting in pain or numbness.
BUT, I recently completed a 7-day, 548-mile tour, and did experience noticeable numbness and weakness in my left hand. That hand is 100% OK now, but I think I need to alter the angle of the bar ends a little. Of course, that ride was over twice what I had ever done in one week, and more than I usually do in a month, so I probably just over did it.
So, there is no one solution that works for all people. The flat handlbar w/ends gives me about 2.5 positions, just like the drops, but does so comfortably. Plus I find the MTB brake lever position to be much more powerful.
You didn't mention any comfort problems with the drops. If it works, why change it?