Aah, minion masters. The proud and honor of PvE. They give several advantages to a team in many many areas and can be a source of great damage, great damage reduction, highly efficient condition removal,...

Though in PvP the rules change and minion masters are generally a BAD IDEA. Many fresh PvP players use minion masters (based on the power they pack in pve), not incalculating the specific details of pvp, which generally don't allow minion masters to work at their full potential.

Note that the use of minions as meatshields in PvP is a bit foolish as players aren't dumb computers and WILL ignore the minions and aim for the players (unless aiming for minions is beneficial).

1) Alliance Battles
I wanted to take alliance battles as a separate item here. Minion masters can be handy in alliance battles due to giving a numerical advantage. Acquiring corpses is generally no issue here due to the 12v12 + NPCs setup.

Important though is that you apply invincinecro strategies (dark bond + mystic regeneration + infuse condition). Players aren't stupid and will go for the master. If you do not have superb survival skills they WILL kill you. (Fast.)

Also (my advice here): take superior runes. Lower health is beneficial on the 55hp-ish survival strategy of the invincinecro, AND the power of minions rises exponentially with death magic (so a good minion master should always have high death magic).

Minion masters in AB are generally a good idea for mobbing tactics.

2) Jade Quarry and Fort Aspenwood
These arenas also have many corpses, but minion masters here aren't such a good idea. Your priority should be capturing shrines, quickly dispatching of enemies, protecting certain NPCs or running amber (depending on the arena and the team you're in). Minion masters tend to be too static for this. Also, these arenas contain a lot of holy damage (RoJ is very popular in both), which is hell for your minions.

3) 4v4 PvP Arenas
Mainly RA. Many players play minion master in RA. Here is why not to:
*4v4 of ppl with (generally) high survivability means a lack of corpses. Aura of the Lich can provide 1 or 2 minions, but those could get dispatched of quickly.
*You only become powerful and durable when you actually have minions. You'll never have as many as you should (max 4-6), and before you obtain minions, you're dead meat. As a necromancer (being rather a priority target), this is not good.
*The time that really matters is the time when your team and the opposing team are equally matched. This is mainly the beginning when all 8 players are alive. When your teammates are all dead, you will not win because you have some minions. When the ennemies are all dead but 1 or 2, your team would win either with or without your 2-5 minions.
*Acquiring minions requires casting animate minion spells, which tend to have long casting times. This is NOT good in arenas where interruption builds are popular. (Practically every ranger carries d-shot, most mesmers and axe warriors have 1 interrupt on their bar too, many rangers also use magbane shot buils.)

Having said this, I must say that IF you are using a death magic build, taking 1 skill that animates minions in an optional skill slot in your build CAN be a valid tactic. You must however, never rely on that skill (for the reasons I wrote above). Also I would like to point out that this is MY opinion, many players do not even believe an animate skill as optional slot can be beneficial at all.