SAF Leo2 was a lousy choice considering saf warplanner always assume enemy number 1 is up north. One of the reason Kor Armor Diraja (KAD) brought the upgraded T72 was the weight. most of the bridges in the country have weight limit under 50tons which the 42tons T72 has no problem moving across. But the 62tons Leo2 will have problems crossing the numerous waterways that dotted the countryside. I still don't understand why SM1 were retired without another alternative light tank. Stridsfordon 90 will be a good choice as it design to fight in thick vegetation.
I am pretty sure that the Leo 2 was not the SAF's choice at all. Do you not consider it strange that there was no competition to find the right MBT for the SAF? Consider that when the RSAF were looking for a replacement strike aircraft, they conducted trials with all the possible candidates including the Rafale, Grippen, Typhoon, Super Hornet, etc. Before they settled on the F-15.
Should not armour be trialing Leclerc, Merk 4, M1, T-72, etc, in Area D to find the best possible MBT? Instead they just awarded the purchase to Kraus Maffei and the Leo 2. This is a totally unproven tank in combat, other then a couple of IED attacks on it in Astan. In one of the IED attacks, the driver was killed, prompting the Germans to add belly armour to the Leo 2A7+ mods. We don't have this problem with M1, Merks, T-72, etc as there is a wealth of combat data on them. You sure as hell do not want to bring this tank into a tank vs tank, and find out that there is a fatal weakness somewhere in the design. Now, if you believe Hans168, and I do, the reason for the SAF only going with the Leo 2 is because of the after market mods that ST Kinetics and Diesenroth could charge the SAF. These included extensive armour upgrades using Dieseroth's AMAPS, and other upgrades inside the turret. if they had bought any other tank other then the Leo 2, the makers would tell them to fuck off as all upgrades would have been done by the parent company. Therefore in this case, I am sure that the tail is wagging the dog. i.e. ST Kinetics is telling SAF what to buy. Its the same for the Bionix too, i am thinking off the top of my head, at least 3 other IFVs that are superior to it.
Regarding the KAD buying the PT-91, i believe at that time, there were 3 considerations. One was the cost, the Poles sold it at a very competitive price. Then they were willing to take Palm Oil delivery as an offset to the cost. And the last is the weight as you mention, as well as the need for only a 3 man crew. But in terms of this terrain and urban environment, its more suitable then a 60 tonnes + tank like the Leo. Unlike the desert environment or open fields of europe, around this terrain, you cannot pick off an enemy tank at 4000m ranges using your superior optics, gun, and ballistic computer. Around here, I reckon engagement ranges will rarely exceed 2000m, more likely in the 1000m range give or take 250m. At this range, the T-72 with its 125mm gun and APFSDS round will kill any Leo just as surely as any decent MBT. At these shorter ranges, any advantages that the Leo has over the PT-91 is largely negated in my opinion.
The retirement of the AMX-13 is also a big mystery to me. It should only be retired after a light tank was found and put into service to replace it on a one for one basis. But ST Eng fucked up the light tank design so badly, I think they gave up on it. And even though the AMX-13 was upgraded to the SM1 standard, the threat environment has changed so much in the last 20 years that really, in all honesty, if we had gone to war with it, it would have been a rolling coffin on tracks for many of our boys. So, I guess they decided to retire it, but not scrap it from what I understand.