England's navy can't be beaten, therefore any land england takes is locked in to the black hole of "england." If they take land in the spice islands it's now in the black hole of "england." If england colonizes it's "england'd." England wins any war by dropping infinite money on one side of the war, so nobody wants to piss off England. Trade companies gives england infinite states effectively, so they grow forever. Eventually england drops every building everywhere, and eventually affords to just sit on their full merc limit (which will be well over 200) and just throw money to infinite merc to anyone they want to.
France fighting Spain? Give me your colony or I'll give France 10k gold. Sweden fighting Denmark? England swoops in and takes the Danish capital and funnels lubeck trade in to England.
As for the army quality, they have 5% discipline which is basically enough to never get stack wiped, and enough to win battles where they out number their opponent, and alone is good enough to (in vanilla EU4) mop the floor with most any Asians. Malacca and their 0 army quality gets wrecked and loses their entire spice island empire. Japan can compete, but Japan will never match England's naval quality so eventually England will kick them off everything back to their Island.