Pedro had worse stats and his goals were against lesser sides. Alexis scored against Real, Atletico, Sevilla (X2). Pedro scored against the weaker teams. Alexis started in a number of big games. Even Tata said at some point he decided to start Alexis instead of Neymar because he sensed he was better prepared for the game. Yes, it's true that Tata used to field a 4 midfielders formation, the fact that Alexis had those stats and performances even without starting in every game, that shows he was one the best wingers (if not the best) in the league last year. Being one the best wingers in a league means dominating in my book. Alexis was one of the players who were standouts in the World Cup as well. What is your point actually?
Pedro scored against weak teams, Alexis scored almost exclusively in Camp Nou.
25 goals + assists in Camp Nou, only 4 goals + assists away from home. That's what you call domination? Barca this season without Alexis is the best home team in the league with the most points and most goals scored, 3.6 goals per game, even more than Real Madrid who are on fire. Mind you, this is with Suarez who hasn't even settled yet and Iniesta having contributed 0 so far this season. Barca isn't a team that is struggling to score at home, with or without Alexis. Alexis was also never first choice in big games under a manager you praised for his tactics. If Alexis was dominating, what exactly is Barca missing without Alexis right now? Okay, you've backtracked a little now and declared "domination = best stats by a winger in the league" but "dominating" and boasting better stats than the wingers of Rayo Vallecano, Getafe, Espanyol, Granada, Elche, Almeria, Celta etc. are different concepts for me, Alexis being better than most La Liga wingers goes without saying.
You are quite vocal about Barca's squad with Cesc and Alexis last season being better and Tata being a better coach than Lucho yet Tata already showed glimpses that he prefers Messi on the wing and to play with a real #9 in big games if possible, something that he is also consequently doing with Argentina right now. Sanchez didn't play under him in big games and would have played even less if Tata had gotten a #9 like Suarez. You should realize by now that Sanchez' time at Barca was up, with Tata or with Lucho.