Well, there would be no oneWorld presence in Central Europe again (first Malev, now AB). The airlines left (IB, BA, AY, S7, soon EI?) are fairly 'peripheral'.
Why am I only seeing mentions of Central Europe - there's Eastern Europe, too. AB used to have 1 daily flight - although in the evening, which made connections to the US impossible without overnighting in Berlin but at least it was an option to having to book with BA - many places besides the East Coast still require an overnight in London but their fees are so high, it's a non-starter. And if you try to get anywhere in Europe, first, you have to pray that the routing is allowed, i. e. going all the way west to LHR and then to go east to your final destination, then, that you can afford to spend several hours in the air many times over what a direct flight would be. All IAG airlines are based so far west, they are useless for Eastern and Central European residents. S7 can't be viewed as quite European, although that's technically correct. So, we're left with AY, which is in a good location but has such a limited network that only suits residents of Finland. So, OW coverage of Europe is awful - it was bad enough with AB but without it, it's tragic.