wow..interesting debate going on here..Lemme put my two cents
in.. 
The SAF's armour doctrine is different in a sense from out
neighbours up north for that matter. Ours is one of mobility
warfare a la' "Blitzkreig" style of warfare. In that sense, we have
a need for light tanks in our ORBAT to fulfil that requirement. If
everyone has realized, the SAF has requirements regarding the width
and size of its armoured vehicles, so that it can cross plantations
easily, be it rubber or palm..
To quote Derek da Cunha's argument, M'sia's overall
strategy is one of a sledgehammer; slow but with a massive strike,
it will obliterate. The SAF is like a rapier; light and fast..but
lethal after awhile...
Yes, our neighbour up north and even Thailand have MBTs in their
inventory...but what is their defence strategy like as compared to
ours? Are they as mobile as we are overall? Where are they
deployed? How are the MBTs employed?
The SAF is able to field MBTs; that's not a problem, considering
our resources, both financial, manpower and logistical. We are
capable of absorbing and deploying these platforms. Question is,
should we follow the path of others in employing MBTs? We have to
also remember that our armour have to cross the straits; not just
rivers and streams. That means that weight considerations have to
be extended towards loading MBTs on our LSTs, as well as the
smaller landing craft. It will then become a balance of how many
tanks we should load, as opposed to AFVs, etc etc...
Tvdog, regarding the Stingray tank...there is some controversy
regarding the vehicle...Thailand is the only country that bought
it. Apparently, there were hull cracks discovered on many of the
tanks, which sparked off an exchange between the manufacturer and
the RTA. You can find that in: J.N. Mak, "Armed But Ready?ASEAN
Conventional Warfare Capabilities," Harvard International Review, Vol. 16,
No. 2 (Spring 1994), pp. 20-24. Hope this helps... 