We can only speculate as to what drives or inspires the Russian figure painters. Until we hear from one directly and can ask simple questions like "why did you paint it this way?" the only disservice we offer them is speculating as to their inspiration, be it artistic, nostalgic or monetary. Other than that, I think it comes down to a case of either you like it and buy it or don't and admire it.
Technicaly,I think they are the best when it comes to portraying brocades and finely detailed fabric. As has been said before, their facial stuff is quite common. Good, but not on the same level of their fabric portrayal. But I must add the caveat of art is subjective and subject to each individuals aesthetic. In short and in a more earthy tone...one man's art is anothers graffitti.
Caravaggio and medieval, renaissance etc painters painted for their patrons. The more color and lavish detail they put into their work the more they were paid. Also it is a common practice to put identifiable clothing and armor on figures in paintings to make a closer assoicative reference. i.e. soldiers are more easily recognized as soldiers if they are wearing contemporary armor. If you look at alot of the 15thc. Lombardic manuscripts dealing with classical mythology they put them in fanciful classical (roman and greek) costume and armor. albeit sightly styleized but still in a refernce and conotation that is easily recognized as ancient by those having access to these manuscrpts and codexes. Conversely artists from these periods would put characters in antique clothing, out of style, or fanciful to illustrate a juxtaposition and create a sense of "wrongness" or tension. Reference Jan Joest's painting of The Arrest of Christ c. 1500, his soldiers hold contemproary weapons but wear Levintine turbans, an Eastern European jacket and german particolored hose, the idea is to contrast between the secular and the profane.
Histrocism in art is not consistent. Uccelo was content to paint SPQR on the shield of contemporary 15thc. soldiers in a martyrdom scene. Contracts with artists did not specify the period scenes should be set, it was up to them and based upon the histrocist bias of the culture they were working in. The direction of Michael Pacher, in an alterpiece comission of a depiction of St George, explained only that the "saints should be armed befiting knights, gilded anfd silvered as needed, and that the "paynims"be given fanciful and mismatched fittings or ensembled with antiquated or fetures long since superceded." Artists would then use what ever reference available to do so. Including extant roman, greek, or previous periods present in artwork, sculpture or other means. (ref Hale, artists and warfare in the renaissance)
They did what may very well be attributed to the current russian fgure painters. By these depictions, they bring the imagination to a new level and away from the sterotypical depictions that were bland and or so detail oriented as to be mind dulling.
I am a little confused though by dariusz statement that this style of painting can be attributed to 18thc styles and takes its inspriation from there. How does this relate to TE Lawrence and his arabic costume? Or periods earlier than then or outisde of Russia. Much of the medieval subject matter they paint can be somewhat overdone as 13thc. english and french medieval soldiers as well as knights wore few brocades as jupons, surcoats and undertunics. A quick refernce of manuscrpts such as the Grande Chronique of france, the Macejowski Bible (actually a mid 13thc french illuminated manuscrpt of the olde testament). the Bedford Book of hours and other compilations of Dutch, french, english, german and spanish codexes and manuscripts show clearly that the clothing was rather plain. Now later periods are a different thing and the russian figure style of painting lavish brocades are well suited for later 14th and 15thc jupons. I don't think you can compare eastern european and western european clothing. its apples and oranges. Although there are some similarities, and crossovers, I think there are distinct differences that cannot be compared.
as for an Osprey style... well Angus Mcbride, George Embleton and others have gotten a pretty good grasp of western european medieval clothing. Since much of their same source is extant examples of this clothing. Reference HMSO MoL Medieval textiles, HMSO, MoL Dress Accessories and you will find much of their artistic interpretation supported. I don't see an equal comparison nor is it fair to denounce either style as better or worse than the other.
What it may come down to is simply a means of what is appealing. To you, or in a mercenary sense, a broader market that is wowed by these figures. It may not be right, nor is it wholly wrong in some cases. The difference is if you are willing to buy the figure for its artistic value or its historical value. Its not often I see figures judged on their historical accuracy. If that were the case, there are alot of "Templars" out there wearing Hospitaler, Santiago, and Teutonic livery and carrying heraldry that is 300 years out of date. Or not appropriate at all.