In my opinion, China can only have limited success in Malaysia due to racial and religious differences, especially if a more conservative leader may be in place in Malaysia in the future. If the Malay and Chinese can really and truthfully integrate, the Singapore/Malaysia relationship would have been better during the pre-Najib era.
Not wanting to touch too much on religious issues here, but if China will become too harsh towards its XinJiang's Uighurs, there will definitely be repercussions here in Malaysia towards the Chinese investments and nationals.
And to add further, even though I'm a Chinese (by race) myself, I wouldn't want to be too reliant on China due to the way they will always do and make decisions unilaterally without any concern for the other minorities. Just look at the way their leaders talk and act as well as their medias publish and their infringements on intellectual property rights, and I know I cannot trust them at all.
I had once spoken to a China lady who is married to a Malaysian in Kuantan. She told me that in her hometown, the developers will come and confiscate their land with minimal compensation. When they complain to the (corrupted) local authority, they were told to pursue the matter with the Central Government and when they do so, the Central Government told them it's beyond their authority because the land is under the charge of the municipal authority there. What a load of crap? That was also how LKY got cheated in the Suzhou Industrial Park (SIP). After a few years, their municipal government copied and set up an exact replica (and named it as The New SIP) next to it offering at half the cost to its clients. Even when LKY brought the matter up to the Central Government, there was nothing more he could do.