Amaravati is good if you are planning for a small and non-commercial capital. it will not have train link but creating access is not that difficult. One thing in coastal AP irrespective of which district you are in, the land is not cheap and will have very good fertile land. To avoid fertile lands you either need to go to extreme corners of Vizag or to Prakasam/Seema.
The challenge to create a capital in Guntur-Vijayawada-Eluru belt is most of the land is a minimum two-crop land if not three crops per annum. There are only few pockets of dry lands in this region.
For some reasons, Amaravati even though is on the banks of Krishna and beautiful etc, there is substantial government land. There are lot of smaller roads to Amravati from Vijayawada, Krosuru, Sattenapalli, Guntur. Muppalla also will become a town from being just a mandal.

In addition you can put nice bridges over the Krishna to Vijayawada-Hyd highway towards Jaggaipeta. The areas on Krishna district side of river Krishna are developed and already conjusted. Amravati comes on the Guntur dt. side of the river but not as developed. Even though this is all river bed these are still high lands at this time.
The idea behind Amaravati as capital is to leave big cities like Vijayawada and Guntur untouched and create a small capital with a lot of road and metro access to Guntur, Vijayawada and also cut through Jaggaipeta to Hyd without touching Vijayawada. It will be like Ahmedabad-Gandhinagar type stuff.
Not a bad idea for a fertile state like AP. The important things needed is more access roads to main roads to create development. It is very symbolic city and symbolism is badly needed to remind the commercial/EJized mindset to think about their glorious past.
Amareswar Temple has a very tall Shiv linga. I have been there three times before 1999. I don't know how the town is now.
If you actually see access wise analogy, Hyderabad was never on the main route either by train or road. All that was built are because it is a capital. Warangal/Kazipet/Hanumakonda is really a good location for a tri-city type development in TG as it will have good train access and comes on Chennai-Delhi route.