I gave it a bit of consideration a while ago, and I came up with a few options for pony weapons.
The most ideal one would be a sort of knuckle duster/ katar - A blade attached to the hooves. The difficulty is with the fact that the blade would be against the ground all the time, which would wear it out, but if there were some sort of trigger for it it would be okay. I figure swords might also be viable with some custom hilts. For example, EP's have proven capable of manipulating something with their tails, so a sword with a ring-shaped hilt could become a very useful weapon. Axes are also viable, because they're a simple enough weapon to use - the blade is curved, removing the need to slice, as it will naturally carve with it strikes something.
Things like lances are a bit trickier to use, since they tend to require two hands set far apart - not somethign a pony can manage. They're pretty much only viable by Pegasi as a charging weapon, or by Unicorns.
On the whole, any pony wielding a weapon physically is going to have to resort to some pretty interesting acrobatics. Quick hooves is pretty much a must for any fighter, at least as far as EP's go. Unicorns can get away with Magic, but if they rely on it they become a
Squishy Wizard - they're effectively useless at close range, where they can be hit with their spells. Of course, that depends on what range of power you alot to their telekinesis. Given the amoutn of concentration, though, I'd say it's not likely viable for a moving target. Same deal with Pegasi; they can get by with weather magic, but they're reliant on the environment until they get windstorm mastery. All three races benefit from having
some form of weapon feat, but Unicorns and Ep's take the most benefit, since Unicorns can manipulate the weapon the easiest and EP's are reliant on their agility, which they have a natural benefit in thanks to their stat boost(at least if they're specced that way). A pegasuses main benefit in a physical fight is the ability to stay out of an opponent's range, and their speed. They don't have to have as much skill in manipulating the weapon if they're quick and agile enough to fly into an opponent's blindspot.
So essentially in combat EP's need focus on Agility and dexterity, Pegasi only need to focus on Agility, and Unicorns only need to focus on their intelligence(Assuming that ties to their telekinetic prowess). All races benefit from Constitution, but it isn't strictly necessary.