I don't really have an issue with this - and you need one who can play top six minutes. A fourth liner doesn't count.
Nowadays, I'm not sure if you need more than two. Skating is a must though. Playoff hockey is even faster and there's no point being tough if you're going to be late to the party everywhere you go.
Tkachuk obviously knows this based on his focus on improving his skating.
it would be great to have another big tough top 6 forward but I do not rule out some extra toughness on the 4th line, which would mean a heavyweight like Reaves.