a handful of decent ministers
Keyword: handful.
I'm not going to argue whether or not they're competent, so let's pretend for the moment that they are. Meanwhile, you have a whole bunch of other Cabinet ministers who aren't competent, far more obsessed with politicking and fingerpointing at the old government, failing to sit down and agree on a unified front for the administration to present to the public on issues, and generally acting like they're still opposition streetfighters in a shaky gentleman's agreement rather than government administrators in a solid alliance. And they are in far more key positions that can make or break an administration than Transport, Comms, and Health. So you tell me if a handful of competent Ministers in good-for-PR positions really does balance a barrel of incompetents in vital positions.
it also serves as a wake up call to every politicians that Malaysians have the power to remove them from power if we deem them incompetent
No.
Both parties know full well that it wasn't the incompetence of the previous government that caused them to be voted out. It was first and foremost the sustained hate campaign run against BN for over 20 years that had begun finally bearing fruit from as far back as the 12th General Election, coupled with Najib refusing to do the right thing in the face of all the allegations and shit against him and ejecting everyone who opposed him. It was Dr. M throwing in his support on Pakatan's side for no other reason but to oppose Najib specifically; it's no secret that Dr. M has been royally pissed at Najib's failure to follow his vision for Malaysia's development long before this. It was PAS leaving Pakatan after the internal split along the Ulama/Professional camp lines led to the Professionals going out to form Amanah, making non-Muslims who didn't trust PAS a lot more comfortable voting for Pakatan.
It was, in essence, the perfect storm that Pakatan were in no way prepared for, having stuck to their old tactic of making wild promises to gain support when they would have literally won with the simple tagline "We're not BN and PAS" at that point.
The competence or incompetence of the BN Ministers had little to do with why Pakatan got voted in, and the competence or incompetence of Pakatan Ministers now will have no effect on whether or not Pakatan stays in power for at least the next 20 (if not 50) years.