HHDL banned Dhogyal for the welfare of the greater many. After much observation, investigation, consulting various teachers/monks/laity decided it would be less harmful for individual practice and the greater whole of Tibetan Buddhism to stop the practice of this one Dhogyal. He spoke for the greater good. What other motivation can he possibly have? What other benefits is there for him?
If you are truly Gelug, then you may adopt the practice of Kalarupa. If Kalarupa is dead or ineffective, then you may search for other protectors. Otherwise if you have Kalarupa, why is there a need to rely on Dhogyal? None of the great seats of learning such as in Sakya or Gelug (Ganden, Sera, Depung) have installed Dhogyal as their principal protector, so why start now. This itself says so much.
Since Tsongkapa relied on Kalarupa as his protector and Kalarupa suited Tsongkapa, then we would be wise to follow suit.
Since followers of Tsongkapa follow the same philosophical tenants as he did, same yidams (Guyasamaja, Cakrasambara, Yamentaka and Kakachakra), same vinaya code, then why not also follow Tsongkapa's protector which is Kalarupa. Why do followers of Gelug follow everything as Tsongkapa did to reach his enlightenment and understanding EXCEPT his protector?
If you are a Tsongkapa follower then follow Tsongkapa's practice completely. Be a clean and thorough Gelug.