Looks really solid, but I think that deck needs 1 Lost Soul (the card can totally flip a game around). I would also max out on Energy Streams because 6 draw cards aren´t enough in a control deck imo. Additionally I would suggest some grave recursion cards, for example 1-2 Morbid Medicine or Corpse Charger which is really up to personal preference, if you value the mana boost and the recyclability through Thrash Crawler over the extra creature you get back or vice versa. My last point of improvement would be the Deklowaz as it is a really slow card with high reward but really slow. I can recommend the use of Blizzard of Spears, as it has the same field removal power that Deklowaz has and has an immediate impact on the game. As for which cards I would cut I think you could cut 2 Bloody Squitos and the 2 pyrofighters (not an ideal card in a control based Deck that really just wants to finish with Bolmeteus and not start to rush with Magnus) for the mentioned 1 Lost Soul, 2 Energy Streams and 1 Morbid Medicine/Corpse Charger. And then swap out the 2 Deklowaz for 2 Blizzard of Spears. If you want to go over 40 cards I would recommend even more grave recursion cards (really needed in a control mirror match), more triggers against rush (for example Burst Shot) and some more draw if you go over 44 cards which I don´t think is necessary as your deck looks really compromised and consistent.