Alright, I'll bite.
First, Tkachev is small, young, inexperienced and small. I can go in depth on this, but I don't really think I need to. No need in giving a roster spot to a 18-19 year old, 141lbs child. Especially in a role on the fourth line against other teams in our division/conference. Tkachev isn't signed, is 19 and has only recently started NA hockey at the junior level. He's built like my niece, and putting him in this position would be awfully hard to imagine.
Second, Yakupov, a 1st overall pick with tonnes of potential will rot on the fourth line. I really don't need to touch on this.
Third, Yakimov, albeit NHL ready in size, is showing flashes in preseason games, but that thought should end there. No need to give him a spot on the bottom line, especially considering he's not ready. I know he's doing a lot with his time right now, but why sit on on the 4th line when he'd be getting top minutes in OKC and a chance to develop?
Also, where do players like Hendricks/Gazdic/Joensu etc go? Do we send them down, risking the lose of the one way contracted players? I don't think it would be a great idea.
Look, I get the shiny toy syndrome and the fact that they're all Russian and there seems to be chemistry between two of them. Sure. It's hard not imagine a line like that, but you have to be realistic.
I get you're new to the board, so don't worry about these posts. Next time, however, look at all the factors involved. There are a lot of cranky people on here though who will pounce on anything they see to be ill-fitting with their perspective.