What do you mean by Everton failing to provide a plan B mate?
I think with a pacey and strong forward, which Koeman has hinted at getting, we will do fine in that respect, added to the squad with Mirallas, Lookman, Lennon and Bolasie (when he's back) they will all provide high levels of pace and Sandro, Klaassen, Coleman (when back), Holgate, Martina (from what I've seen), Davies, Dowell and Gueye aren't exactly sloths, not as fast as the first 4 I named but they all have a good burst and certainly aren't slow. There are more tactical ways to play the game than just relying on majority of your players having pace to burn. Most wingers in the league have pace in abundance and beat their man often but have no end product so it's all in vain.
Regarding Koemans ability to build an attacking unit, I have to disagree with you. Ok he's not setting the world a light with frequent 4 goal victories but he's had 3 seasons in the league with average teams bar the odd few players and in 114 league games his teams have scored 175 goals which is an average of around 1.5 goals per game if my maths is correct. Martinez' 3 seasons in the league with us yielded less goals, falling in at 168 gls in 114 league games and we actually scored 1 more goal last season (62 GF) than the we did the season we finished 5th (61 GF) with Martinez, yet you frequently sing his praises but not Koemans who's better defensively as well as offensively. Remember leagues have been won with a good defence and 1 nil victories.