Back in the good old days, prior to 2000, there was a charming Russian lady at the Russian Consulate in Edinburgh. No queues. Visa applications were a breeze.
Then 12 years or so ago, it all became much more difficult. Possibly the quid pro quo for the difficulties Russians experienced in Moscow attempting the near impossible task of applying for a tourist visa to visit fortress Britain.
European nationals from Schengen Treaty countries probably find it much easier.
Part of the problem in Britain is that unlike some countries, we only "count them in" and do not "count them out". So at any one time the Home Office has no idea how many foreign nationals there are in Britain. Secondly there are no restrictions on where visitors travel to or stay with Britain. In Russia visitors have to be registered with the authorities by the hotels they stay in.
As has been commented using a reputable online agency to obtain the visa support makes it easier but the service is expensive. It used to be said that a Business Visa opened doors much quicker.
I have not been to Russia since 2006 so I am not current, but it used to be much quicker to pass through immigration at Domodedovo than standing in line at Sheremetyevo, which is probably nearly as bad as Luton in the high holiday season.