The timings of 19210 that you mentioned are the worst for someone who wants to take the Humsafar or Duronto from Jamnagar or Hapa to Mumbai. 19210 leaves Okha at 15.15 and reaches Jamnagar at 18.33 and Hapa at 18.50, which is around 19.00 when you are at the Jamnagar or Hapa station. You can easily catch the Humsafar that starts at 20.15 from Jamnagar or the Duronto at 20.05 from Hapa. Basically, 19210 connects the Humsafar and Duronto at Jamnagar and Hapa so that passengers who couldn't get tickets on the Saurashtra Mail are at least connected by these trains to Okha. We saw in Megha Shyam bhai's trip that there is almost an hour gap at Jamnagar to catch the Humsafar when you arrive on 19210. Speeding up 19210/09 will benefit passengers going from Dwarka to Botad/Bhavnagar but it will mess up the schedule for passengers going to Surat/Mumbai as they will have to find cars or buses from Dwarka to Jamnagar to catch 22924 or 12268.