The problem with the British position in Malaya was that a) it was really rather poorly defended, b) there was a large amount of information asymmetry between the British and Japanese capacities, c) the geographic nature of Malaya makes it extremely difficult to defend without naval and air superiority, neither of which the British had in the region, nor did they have the capacity to reinforce, and lastly that the Japanese commander, Tomoyuki Yamashita, was quite a competent commander that Percival simply could not overcome.

British defenses in Malaya consisted on paper of 2 Indian divisions, elements of an Australian division, and later a second-line infantry division was shipped out in January 1942. However, these formations all had their combat ability significantly hampered. The Indian divisions had most of their experienced members in India forming training cadres in part of an effort to mobilize and expand the Indian army (which at the time was extremely weak). The Australian division, while capable, was split up into several areas and was defeated in detail. The British division had only recently been raised, and was deployed to Malaya and quickly committed to battle without much time to adjust or to really be prepared. Given the situation, the three divisions and tank brigade that the Japanese committed-especially the formidable Imperial Guards Division-who had all prepared for this operation thoroughly, and were well-equipped, motivated, and led, not to mention the air support (naval bombardments were generally frowned upon by the Japanese navy as a waste of ammunition, and the Army and the Navy didn't like working with each other on a "good" day). For that matter, the British in Malaya simply did not have the quality nor quantity of fighter aircraft to contest air supremacy against the Zeros deployed by the Navy Service and the Ki-43 Oscars by the Army Air Force. The defensive configuration that Percival had chosen split his air assets between Northern Malaya and Singapore as he had anticipated that the Japanese would land there and they could intercept Japanese shipping before they could land. However, the Japanese actually landed on the South side near Thailand (likely due to the fact that they had acquired valuable intelligence on the state of Malaya's defenses from documents captured by a German commerce raider). Because of the fact that a large area of Malaya is mountainous (specifically, in the middle), this meant that the Northern Malaya troops were out of position, and more importantly a rapid Japanese advance would threaten their connection to Singapore, leaving them cutoff from supply. This endangered the flank of the troops station on the Northern side so the British were essentially forced into a fighting withdrawal that quickly left them stoppered up in Singapore where they were surrounded and quickly running out of supplies.

The British did not have very good intelligence on Japanese capabilities. For instance, they failed to appreciate the range of the Japanese aircraft flying out of Indochina, nor did they have any idea of what Japanese intentions were-while the Japanese had pretty much all the intel they wanted. This is why for instance Force Z was exposed to air attack and destroyed so quickly. There also was to an extent a certain dismissal of Japanese combat ability that was rather quickly dismissed upon first contact.

The last thing to consider is just how better prepared the Japanese were, thanks to the planning of their commander, Tomoyuki Yamashita. He had arranged for his troops to be equipped with enough mobile artillery that severely weakened the defensive positions of the British troops, and had landed them in a way that avoided the strong points of the British defenses and endangered the British position. Contrary to popular belief, the British didn't, for instance, deploy their fortress guns against the waters in the south-in fact, they were redeployed and used against the Japanese in the North-but due to the fact that the guns were only really equipped with armor-piercing ammunition (for use against ships), rather than high-explosive or fragmentary, it made the British bombardments significantly less effective. Even so, the Japanese were running out of supplies-but the British didn't know that, while they certainly knew that they were running out of supplies. As a result, in an effort to protect non-combatant civilians in Singapore, Percival ended up surrendering. Now, it is certainly possible that he could have tried to hold out longer. But the rest of the British Empire was in no position to assist and he hadn't been dealt a particularly strong hand to begin with. So while it is clear that a more competent commander in Percival's place might have been better able to resist longer against the Japanese (especially when the Japanese logistical situation was also in dire straits), ultimately it would have had the same ending and with not much more strategic impact.

Sources:

Thompson, Battle for Singapore

Tsuji, Japan's Greatest Victory: Britain's Greatest Defeat (WARNING: EXTREME JAPANESE NATIONALIST BIAS AHEAD)