The obvious advantage of Goblins, and possibly a good enough reason on its own to have them is for the Throw Team Mate (TTM) option. However they also offer interesting options as a "receiver" giving the Orcs a possibility of developing genuine catchers.
Within a standard Orc team I'd recommend having one or perhaps two goblins on the squad, developed to provide TTM capability or as an additional receiver for those short (2-3 turn) drives you occassionally need to make.
Sometimes it can be fun to build alternative teams that utilise goblins more extensively. Against many rookie teams (pretty much everyone apart from Dwarf, Chaos Dwarf and Norse) Goblins can be very annoying, Stunty and dodge can combine to give mobile pieces that are hard to knock over. Against players without block goblins are less likely to have their armour broken than a thrower would (although the thrower would stay on the pitch more!). Under LRB4 rules a 4 goblin starting roster offered the advantage of freeing up cash for fan factor, rerolls and other positionals. However under LRB5 that need for early cash has largely disappeared so does push longer term team planning that way.
Goblins are very easy to play badly. Generally speaking good opponents will seek to blitz/block Goblins as much as possible with their Block/Tackle/Mighty Blow players. This is an attempt to remove the weakest pieces from the board enabling them to bring better numbers to bear against your stronger and tougher players. So:
- Avoid leaving goblins in positions they can be blocked.
- Avoid ending your turn with goblins next to block or tackle players.
- Do NOT run goblins downfield unsupported.
- Keep goblins away from positions where they can be chain-blocked (i.e. blitzed or blocked onto another player for another block).
- Do NOT think stunty means you should always run through lines. Goblins fail one dodge in nine.
- Goblins make good ball carriers. They are as fast as Blitzers, and with stunty and dodge find it easier to escape from trouble. Sitting in the middle of the cage is safe too.
- Goblins are good at providing assists in difficult situations. Try to ensure you don't leave them standing next to players.
- Goblins are as good at fouling as any of your other players - and less valuable so less worrying if they get sent off.
- Goblins can be thrown by the troll. Always fun should you be without another option - but don't use it much as its very unreliable and normally there is something better for the troll to do.
- Goblins are good for running through the lines and grabbing loose balls or marking ball carriers.
- Goblins are handy for running into sideline cages blitzing ball carriers into the crowd.
There are many tips to a good TTM play. First of all remember the Troll can move before picking up the goblin. So if you have two goblins put both on the LOS and then run the troll one square into the opponent's half to make the throw - meaning one less square you need to move the goblin.
Don't forget that you need to get the ball to the goblins. So set up your throwers, blitzers and line orcs to try and cover as much of the field as possible and at the same time be able to get adjacent to a goblin for the hand off. As the ball could land anywhere you should either set back far enough you need all your movement or a single GFI to reach the goblin. Don't set up for both GFIs to get to the goblin as you want to allow a little bit of wiggle room should the ball land off your route.
There are two "double-less" progression routes for goblins which are the standard ones I'd consider in an orc team, and then alternatives to consider should you be lucky and get a double.
Defender - the defender goblin specialises in being really annoying to the opponent. Sidestep then diving tackle. If are lucky enough to survive to a 3rd skill Jump Up is probably the best option, but sure feet/sprint are also good considerations.
Receiver - built to either run with the ball or sprint downfield and take the catch. These are the main build that Orc teams really benefit from. Catch, Sure Feet, Sprint. Diving Catch under the experimental rules is also interesting, but it doesn't help with hand offs so doesn't help with TTM - just a standard receiver role, so gets demoted to 4th.
Fouler - Doubles first and take dirty player and follow up with sneaky git (or feel lucky and start with sneaky git!). A DP/SG Goblin still adds 90k worth of value however he gets good odds making fouls on almost any opponent and SG means you don't need to worry about loading up with assists.
Guarder - guard on doubles sounds like an odd choice, since it implies putting the goblin in harms way. However goblins can get where no one else can reach and hyper-mobile assists are always good. Throw in sidestep and you've a nasty little problem for your opponent to solve.
Blitzer - strip ball, wrestle or dauntless are all double options that basically try and convert goblins into genuine blitzers. This is once again to take advantage of their mobility in order to break down cages. Combine with Jump Up, Sure Feet and/or Sprint to increase range or Sidestep/Diving Tackle to increase annoyance should you get the ball loose
Retriever - sure hands on doubles. Once again using the goblin mobility to get anywhere to have the player that goes and gets the ball out of those tricky spots. Speed skills to help you get there, SS/DT to help should you fail the pick up anyway. Block on a subsequent double gives you a good ball handler in many situations.
Stats - +ST goblins are interesting players to have. They suddenly become real competitors for blitzing as they can get to places that no other player can. Subsequent doubles for blitzer build (wrestle, strip ball) will make them feared whilst they last.
+AG - probably the best increase you can get on a goblin. 2+ dodges anywhere is awesome. There just won't be a defensive line they can't waltz through. It also makes them better at picking the ball up and catching so a retriever or receiver build makes a lot of sense.
6,4 - I'd always take the +MA - goblins won't live long even with Av8, whilst MA7 makes them much better receivers as they can score in two turns without going for it.
All in all Goblins offer something different to Orc teams. Some games they will be gold and deliver exceptional value for a 40k player. In other games they will be a liability where they just get cas'd on the first turn and leave you short handed.
If you like your Orcs slow, predictable and conservative then Goblins probably aren't for you, but if you like having some different options try one.