The concept of Rajdhani is provide good connection to a capital/industrial hub of a particular state to the country capital rather than focusing on the intermediate stations. I've also seen both NDLS-BCT Rajdhani and August Kranti Rajdhani. Both have halts at Kota but not many people prefer it for travelling b/w Delhi and Kota. People opt for either Jan Shatabdi or the other trains(there are many options). Other than inconvenient timings, Jaipur and Ajmer have got more options for Ahmedabad. Rewari and Alwar haven't got many(only 2 trains actually). Ashram is always full and Garib Rath also gets full as it's connecting Delhi Mumbai. So halt at Alwar is quite important. IR can actually try an experimental stoppage for a month or 2. And about skipping Jaipur and Ajmer, Rajdhani can't. Both are 2 of the 3 A+ stations in Rajasthan and important tourist places.