Too radical? He was removed because he couldn't be bribed. Kremlin wanted to end the war in Donbass, as many of the stooges were having their bank accounts frozen. Strelkov was given the orders, but he refused to obey. He wanted to liberate Mariupol in particular, which is home to the strongest partisan movement in the region.
In my humble opinion, both parties (regime in Kiev and rebels) were overstretched and needed a break from war - hopefully a permanent one. I don't think that rebels had enough strenght to liberate Mariupol, at least not without huge losses -that's including local civilian population- which was totally unacceptable.
Look. Kiev failed to defeat the uprising, and rebels failed to free more than (roughly) 1/3 of the Donetsk and Luhansk regions combined. Rebels also failed to gain massive
active support outside of the territories they are holding. It is pretty obvious that ethnic Russians and Russian-oriented Ukrainians in the south-east aren't very interested to take arms and fight (same as Ukrainians loyal to Kiev aren't, just look at that joke called 'mobilization'). But people will give their vote to Novorossiya - be it federal, confederal or independent.
That's the goal - first, to stop this bloody civil war in which everyone living there are losers, and second: to start a democratic process in which people in Donbass and other regions should get an opportunity to think and decide about their future in relatively normal conditions. Not only Mariupol but whole bunch of other towns, now far out of the rebels' reach, may then easily join. Peacefully. Isn't that something we should be all striving for?
