However, numbers aren't the only thing that determines a PC's power. What about their special abilities/powers/skills/spells/etc.?
After all, a bunch of low level orcs won't be much of a threat if you can just fireball them/fly over them/mind control/etc.
Some abilities can just win no matter how high/low the numbers are. How does NEXT handle them?
Well the DM should initially determine the level of magic in ones campaign -
Invisibility, Fly...etc do they exist?
If they do exist, perhaps it is difficult to acquire such spells without training or they're long forgotten magic; perhaps there is an additional cost in casting them (HD..etc); or there is a limitation where due to the wizards constant contact with magic he risks be infected with a magical disease should he cast more than 1 spell on himself for the day;
If you decided to play straight up magic as it is written, well then you should also account that the opponents would have access to the same magic:
Perhaps there is an orc shaman among the low level orcs who dispels the
fireball.
Orcs have bows let them pepper the wizard as he
flies towards them, if he gets to close they hurl a bolas limiting his somatic gestures, or they open the chest they have been carrying and release their pet dragon they've just captured.
Mind Control....hmmm always a risky business...what if the Orc's mind he controls is shattered, perhaps it has multiple personalities, perhaps there is a dark past to this orc which is revealed (introduce next story hook)...
perhaps this experience begins affecting the wizard: cant concentrate for long periods, disruptive sleep..etc
I do not see a problem. Make the magic system your own and if not play with the possibilities.
If you decide to use orcs as an encounter in your medium to high level campaign then you have to decide is the encounter a resource depleting one or is it part of the BBEG fight. As part of a resource depleting one, you have succeeded (Fly, Fireball, Mind Control) spells used up, perhaps one orc gets away an the next orc patrol is more prepared. If however if it part of the BBEG, well then the responsibility rests on your shoulders to ensure the orcs are capable of challenging the party - through clever tactics (like a hidden net falling from the cavern ceiling capturing the mage), magical items, spells, levels and/or class abilities.
NEXT has allowed for a low level Orc to still injure a higher level PC through bounded accuracy, but not necessarily to withstand higher-level spells and class abilities. You have to be fair to the system and toughen up the monsters encountered if you want to challenge the party.
