Hello fellow frog fanatics!
I have been testing 3 rosters in WC-rules tournaments and one-offs.
First of all I don't think there's a perfect roster out there. You absolutely can't have everything that you want, so you have to decide what you can best live without. There will be games where that works perfectly, and games where you really needed an extra reroll. Or an extra Blitzer. Or whatever.
The constants in every roster I've been using are:
3 Rerolls - this is an absolute minimum with Slann. 3 is actually a little bit low, and implies that I accept turnovers on low risk or low percentage plays early in the half, because turn 6-8 plays tend to be the critical ones on both offense and defense and I have to save rerolls for that.
12 Players + Apoth. Slann can play okay while outnumbered, but at some point, each player lost just makes the game exponentially more difficult. Not to mention that the Apoth is a great value - spending 50k to keep a skilled, expensive player on the field is a win.
4 Catchers - they're the playmakers of the team. Slower but even more mobile Gutter Runners. Diving Catch is situational but awesome when needed - catch an accurate pass on 2+ in a tackle zone! Save go for its by passing to the square behind your catcher! Get free catch attempts at throw-ins and kickoffs! And most hilariously in a game yesterday, catch bombs thrown into the cage and toss them right back!
Anyway, the 3 rosters I've been using are:
"Smeborg Special"
4 Catchers, 8 Linefrogs, 5 Rerolls, Apoth
I can't claim credit for thinking of this roster, all thanks go to Smeborg. This is gloriously simple - attack the cage every turn, knowing that you have rerolls to spare. Playing this roster, putting the ball on the ground is almost trivial. In theory, at some point, you'll get a good bounce, grab the ball, score on defense, wash, rinse, repeat. In practice, the ball often bounces into many tackle zones and play degenerates into an ugly scrum, which ends badly as often as not. I should say that this has been an issue with every Slann roster.
About half the time, I had rerolls left over after a half with this roster. "That means everything went well, awesome!". But it also means that the additional rerolls were wasted TV which might have been better invested in players. And of course there are games where 5 rerolls aren't enough ... ...
"Two Blitzers"
4 Catchers, 2 Blitzers, 6 Linefrogs, 3 Rerolls, Apoth
This is the most Blitzers that I can field while fulfilling my requirements listed above. The theory here is that the Blitzers (MA7, Jump Up) are faster than the Linefrogs and just as effective jumping into cages - if they save one reroll each on GFI, then they're a straight upgrade over Linefrog+Reroll. Jump Up also gives options even if you fail a leap - as long as they're just prone, in the cage and next to a ball carrier, they're a serious threat and opponents will have to move the cage or try a risky foul.
In practice, this has been my worst-performing roster on defense, although it's also the one I've played the least.
I also intend to test out the variant with 1 Blitzer and 4 rerolls. Sort of a compromise between this and the Smeborg Special.
"Kroxigor"
4 Catchers, 7 Linefrogs, Kroxigor, 3 Rerolls, Apoth, Coach, Cheerleader.
This is the roster that I've played the most. As with any Big Guy, sometimes he giveth, sometimes he taketh away with untimely turnovers or awful Bone-head rolls.
But the Krox is probably the most reliable and useful Big Guy in the game (for whatever that's worth). The leap-cage-crash play usually involves tagging up at least one side to cancel assists. The Kroxigor is much safer for this task than a Linefrog, both because he's harder to hit back, and it makes it more difficult to move the cage. He also takes a lot of pressure off of the rest of the team by marking 2+ opposing players; either they commit more players to assists and knock him down, take risky dodges away from Prehensile Tail, or leave their players there. Either way, that leaves fewer opposition for the rest of your team to deal with! Meaning easier movement, fewer dodges/leaps, easier blocks.
Speaking of fewer opponents to deal with, I don't block with the Kroxigor often but when he does, he hits hard. He was instrumental in a pitch clear (!!!) vs Vampires yesterday (along with some generous assistance from the Vampires). I don't expect to clear the pitch every game with Slann (I don't expect to do so ever again actually) but the Krox can put some fear into your opponent and that can be valuable.
The coach and cheerleader are a bonus - but nearly a third (10/36) of all kickoff results are Brilliant Coaching or Cheering Fans. A +1 bonus on a d3 roll is significant, and any extra rerolls are always welcome.*
* - the quick back-of-the-envelope math on Cheerleader+Coach is that you roll Coaching/Cheering 10 times every 36 kickoffs, and a +1 bonus gets you a reroll which you wouldn't get otherwise one-third of those results. So you get an extra reroll every 10/108 kickoffs (9.25% chance of an extra reroll per kickoff).
This discounts extreme situations - if for example you have +2 FAME and your opponent doesn't have any cheer/coaches, you'll always get a reroll from those kickoff results. And the value also varies based on how many kickoffs you have per game - there are games with only two kickoffs (17.6% chance the cheer/coach win you a reroll), many games with 4 kickoffs (32.2% chance).
Naturally there's the same chance of turning a tied BC/CF roll into a win, which doesn't get you a reroll which you wouldn't have gotten anyway, but which does deny one to your opponent. That's valuable but doesn't help you directly.