I was with you until you mentioned Vassell.

Man Utd have inflicted some of their attacking malaise on themselves by signing attacking players with no pace (Mata, RVP) and selling or loaning out the few players with pace they already had (Nani, Zaha, Welbeck). Zaha could be a good long term prospect if he could sort out if his off-field problems.
I agree with you that slow based tiki-taka is not in Man Utd's DNA. For the past quarter of a century the team's style of play has been a manifestation of Ferguson's personality on the pitch: daring, fast, adventurous, risk-taking, cavalier. Real Madrid's former coach Vicente Del Bosque once referred to it as Man Utd'd "tactical anarchy" (AKA they were quite willing to go toe to toe with anyone, never took a backward step, and were willing to dam* the consequences).
Coach wrote:
Tactically, United do not have the setup to lay siege to Precinct 13 let alone a West Midland's rearguard, midwinter. In days of old the ball would be flying out to the flanks for marauding runners to hit the byline and throw it into the box. Today, their game is perhaps more cerebral, with slow transmissions at the synapses. Van Gaal is still trying to sell the world his 3-5-2, despite United's DNA baring the genetic code of its exact antithesis. Its all too slow on the Mancunian front, but, that said, they're picking up points, getting some wind under the sails and could well take off, with a little tinker. A few pacey blacks and they're back in business, Big Yannick Bolasie one side, Wilfred Zaha the other....zoooooooooooooooooommmmmmmmmmmm!!!!!! Darius Vassell through the middle, still got it over the first 20 yards!