Because the -6R is common to all nations. The -6M is only manufactured by the Free Worlds League, presumably as their primary variant. The -6K is made in the Combine, and seems a bit less frequent that the -6M. But both nations still produce the classic -6R.
The last dozen battles I have played in have all had a Wolverine 6M -- fielded by Davion, Steiner, and even Comstar.... as well as mercs, and in random pick up games. For the BV cost, it's a VERY solid design, and doesn't have the weaknesses of the supposed standard version. And in the hundreds of games I have played over the years, the answer to the 6R being common to all nations was that since this is a canon variant, the factories can make to these specs.... or it's "captured".
This is where the complaint that customs break the game starts, in my opinion, to lose ground --- unless you force a faction only, specific year only, game... then the variants, which are canon, become fair game. And, under those rules, you can have some very bad abuses, with nothing but published canon designs. And, as the canon designs are made under the same rules that any variant is built from.... and also considering that this is the first time that the construction rules haven't been in the same book as the standard rules..... (and yes, I still have one of the white booklets with the unseen Shadowhawk on the front cover, and the construction rules, which haven't changed much, are in there).... then the issue is more that the abuses that are possible need to be understood.
As I have suggested before, every player needs to play a game where they automatically lose initiative to the other side..... why? Because, even in the example above, the whole statement about MASC was compounded by the statement that if they win initiative, they have a back-stab. For that matter, almost every example of "game breaking" tech or other complaint I have seen here has been based on the effect of initiative. That makes me wonder if the initiative system is broken....... Why don't we roll a pair of die for each unit, and then move them, starting with the lowest number first? Or, by lance or pairs, in larger games?
For that matter, ask your fellow players, and most will tell you "if I win Initiative, I am doing this..... and if I lose, I am doing that. This is decided before the die is even rolled, and before there is a chance to see what an opponent does, and react... which is what initiative is supposed to actually simulate. This is also routinely decided, regardless of objectives or other factors... unless you use very rigid objective or support rules.... such as forced withdrawal, or statements such as Side A cannot retreat unless......
In the end, I have yet to find any real game breaking tech..... not even customs can do it. If my opponent fields something with large numbers of IJJ.... I usually have either some area effect weapons.... or something fast enough to take away some of the advantage.... because I usually aim for a rounded force. A pair of Flatbed trucks with Mortars (
http://www.masterunitlist.info/Unit/Details/1131/flatbed-truck-mortar ) can almost always be squeezed onto a unit to provide some support for it. And if said player goes for the trucks, then use the trucks as bait to box him in, and pummel him when he goes for them.
Also, if he is jumping constantly, then he is either paying a +3 to hit, or using better pilots and gunners, or TC's and Pulse Laser.. all of which cost, and all of which are available to you as well. If your opponent can use them, then so can you....... And no, you are NOT forced to use IJJ's to counter them.... I have done very well using ERPPC's and cover to force my opponent into close range..... along with LBX guns, or equal pulse lasers of my own.
I have lost games due to new stuff... and I have had to adapt my tactics on the fly to deal with things...... I've also played Word of Blake, and had my opponent take the ECM variant of every mech he fielded... along with ECM vehicles, and a Karnov flying around dropping portable ECM's to boot. So, yes, my force built along the standard C3i lines had issues.... and the next game, where I fielded Blake units, but deliberately chose ones that did NOT come with C3i, as I knew I wouldn't get to use it anyways, provoked a complaint, as my opponent did the ECM swarm again, and left himself short on firepower...... By using standard canon variants, most being either 3025 designs, or 3050 - 3060 designs without streak missiles, or C3i...... I "broke" the game, per my opponent.
Every time I have seen the complaint of the game being "broken" it has been by one player with a specialized force, facing another player with a specialized force, at which point, it comes down to whether or not those specializations interact, or whether one of them was specifically a counter to the other..... If I field an entire force of fast units, and you choose nothing but 3/5 assaults with orders to chase me down and destroy my unit... expect me to get my unit off the field.
If I take a company with a total mech weight of 240 tons, and try to hold the line against even an average inner sphere force..... I will lose. That's the nature of the game, and hardly anything that can be considered game breaking.
At the same time, I do consider it a courtesy if my opponent lets me know he is using some new tech ---- In a recent game, my opponent took Plasma Rifles to counter my light vehicles and battle armor..... Did this make the game broken? No... but I had to do some quick re-thinking as my fast strike forces were suddenly in a position to be decimated..... So, I used them as the follow up hammer, and ensured that my heavy or bigger mechs were always a somewhat better target, and used them to draw that fire off...... in essence, I gave my opponent too many choices, and it allowed me to actually control the flow of the battle... and that's despite losing 2/3rds of the Initiative rolls.......
So, again, I have yet to find any "game breaking" tech or tactics --- I have found some that can be annoying.... but dealable ----- just adjust the tactics.
And to let you know how I dealt with my first taste of IJJ.... I pushed the player over towards the edge of the field, via relentless advance, pounded his buddies.... and used a spread formation, where every attempt at a back shot on one of my mechs put him in short range for potential back shots from my following lines......he finally went for it, and took a Gauss to the CT rear from the next mech that was 5 hexes away.....
Nahuris