What is the design BOTTLENECK of a RF transceiver?

For general wireless communication, power amplifiers may be the design bottleneck, because the linearity and the efficiency are hard to balance, right?

For satellite communication, filters may be the design bottleneck, because the requirements are much higher than that of general wireless communication, right?

Plz help, thanks!

Hi,
I'm designing very high power amplifier for wireless communications (2 kW), in my case efficiency/linearity is the bottleneck.

For satellite communications I think that the bottleneck is LNA, but also good efficiency is important, and good response to extreme enviromental factors such as low/high temperatures, inmunity to cosmic radiation etc.

I saw many papers on PA and filters, so I guess that they are more difficult to design than other modules in a transceiver.
For example, there are many papers on PA linearization, and novel filters to improve the passband's shape. There are also many professors specialized in PA and filters in college.

I don't know much about LNA, are there many novel designs for satelltie these years?