*sighs* Fine. Since you require it:
The issue is playability and game balance. The argument against SR4 dikote is that in SR2 and SR3, in comparison to the much tighter damage codes in SR4, it didn't do much.
I was actually looking at Dikoting as something to write up for the 1st issue of the Dumpshock Datahaven, and I talked with a few folks about it back then.
Mechanically, Dikoting became a problem due to the much narrower definitions of damage codes. Dikoting was cool, but it didn't provide a massive bonus in SR2/3. Now though, a +1 to DV is huge. It just doesn't fit as well into the current iteration of the rules, sadly.
Unofficially, the explanation I give is that Dikoting has become superfluous. Modern techniques at metalcrafting have made weapons and armor innately stronger, and while you can still spend the nuyen to Dikote something, it doesn't actually improve it any because the material is already at the Dikote level. All Dikote really does now is "bling it up".
This is your explanation. Mine is simply that those writing the rules have not yet decided on which way this is going -- mainly because for the most part dikote
has not yet been mentioned. If somewhere in the game designer conversation on ammo, modifications, or armor it said, 'for those of you who miss dikote, it's gone. <Insert explanation here>', sure, it no longer exists. Instead, in
all the publications to date, it's mentioned precisely once -- in the game description of the Aztechnology Cuanmitztli Main Battle Tank ('dikote mesh plating',
War!, p.168) -- which means that the game designers have yet to make a hard decision.
My argument
for it is that every other type of weapon has an armor-piercing (APDS or AV) technology. My reply to Bull's post above was as follows:
That makes sense if there's nothing else comparable, but -- like with the original Dikote -- there is: APDS / AV rounds. My interpretation would simply be that a) dikote adds +1 Impact only to armor with ceramic plates (i.e. you're dikoting the plating), and b) adds the 'Anti-Vehicular' characteristic (-4 AP vs. people, -6 AP vs. vehicles and barriers) to a ceramic or high-temperature metal (steel, titanium) edged melee, thrown, or projectile (as in arrows/bolts) weapon. It cannot be added to any sort of high-speed projectile, such as firearm/gunpowder ammunition or gauss rifle ammunition; get AV rounds if you want that.
Anyhow. The debate continues from there. My apologies that I didn't want to repeat the issue.