Hi Helge,
given that ARMv8 A57 can run at speeds of 3 Ghz (our current DB server runs on an an Intel Xeon E5-2670 with 2,6 Ghz) pure computing power shouldn't be the big issue.
Hadoop was demonstrated on the upcoming Opteron A1100 (AMD cosies up with Oracle over Hadoop | News | TechRadar) so I could imagine running (at some point in the future) application servers on that platform. If phones and tablets are able to render HD videos why should such an SoC not be able to run an ABAP-VM or even an AS-Java - given the possibility to densify the current (blade-)datacenters even more while at the same time "greening-up" the IT by using less power and cooling.
Markus