What ways are there to either reduce power point costs or increase the effective manifester level for a psionic power—apart from Overcharge, the wilder class in general, or the torc of power preservation—, so that the power is augmented beyond the usual limits set by your manifester level? Even if the method works for a single power, or a single manifestation, it is still useful.
[RPG] How to a psionic power be augmented beyond your usual manifester level
pathfinder-1epsionics
Related Solutions
The most powerful way to bypass the Focus expenditure requirement on metapsionic feats is playing an Ardent and using the Dominant Ideal ACF. A Dominant Ideal Ardent does not need to expend their Focus when applying metapsionic feats to their chosen mantle.
Another way is to play an Elan and take the Elan Retainment feat (from Complete Psionic), allowing you to not lose your psionic focus once per day when you otherwise would.
A third, but mostly inaccessible way is Epic Psionic Focus, allowing you to power two feats with the expenditure of one focus.
And you have already discovered Psicrystal Containment, the most accessible way by far.
As for whether it's possible to use two metapsionic feats at once - yes, it's generally assumed you can combine the uses of two or more feats, as long as there are no action incompatibilities. Also, for what it's worth, the FAQ seems to agree (page 93):
I have a question about psionic focuses. Psicrystal containment allows you to use your psicrystal’s focus instead of your own, and Epic Psionic Focus allows you to use the same psionic focus to power two psionic feats. What isn’t covered is whether you can expend two psionic focuses at the same time. Can you use both your own personal focus and the psicrystal’s focus in the same round? For example, could you use your personal focus for Deep Impact and your psicrystal’s focus for Psionic Weapon on the same attack?
You can use them simultaneously if you are doing different things with the expended focus, but if you are using two foci simultaneously to amp damage on the same weapon, it probably doesn’t work—unless the DM feels there is a good reason to allow the combo. I could certainly see this being allowed in some cases.
To answer the question at the end: Yes, the "trick" of using Sneak Attack with a power like Energy Ray works, and can yield a relatively high number of damage dice per manifestation under good circumstances.
To answer the question implied by your title: Hardly. The Psychic Rogue is harshly limited by his power list, power point total and feat availability. Consider the damage potential of any full manifester using multiple actions/round and (preferably multiple) metapsionic feats.
The short version: It works, but it's less awesome than you think it is. Full manifesters do blasting better, let Psychic Rogues stick to... rogue'ing.
Best Answer
Metamind
This Psionic PrC is the simple answer to more manifesting. It doesn't break the limits in an extraordinary way, but it does several useful things:
1) It grants more power points, which is essentially reduced costs aka more manifesting per day.
2) The capstone quite simply says that once per day for 1 minute you gain some defenses and infinite manifesting. Doesn't say he can actually exceed his manifester level, but zero cost powers for the duration of several encounters is really legit
Access: Level 6 to get into the class, level 16 for the capstone.
Vizier
This is an out-of-the-way base class from Dreamscarred Press (same people who did Psionics for Pathfinder). Akashic magic is totally legit, and this class is 10x more awesome than it seems on the first read. I could rave about it, but I'll cut short the rave with telling anyone who reads this to play this class through level 1-20 just once, and you'll realize how fantastic it I (no...seriously. Do. It.). ANYHOW, the key part you care about is thus:
1) dipping into the class, just 1 level will suffice. The class also has other synergies with just about any class that make it surprisingly useful, even at level 1. A 3 level dip would be worth it, IMO, but 1 level is all you need.
2) Taking the Akashic Augmentation feat. This allows you to invest some of your essence (kinda like power points for Akashic magic) into the feat, reducing the power point cost of a select power. Limited, but nifty.
Access: Dip, so whenever.
Cerebremancer
This Psionics PrC is your best bet. Dip into an arcane casting class, and then take this dual-progression class. It progresses your casting, meaning you end up getting spells from that dip (useful) but the key part is that you can sacrifice spell slots to boost powers for free. When you are talking things like 9th level spell slots you’re sacrificing, that is a huge augmentation and boost to the DCs. How this interacts with manifester level isn’t clear, but ostensibly it bypasses the limitations since you aren’t actually augmenting the powers. Even if it doesn’t, though, you’re dropping the cost ridiculously. Excellent choice for any super-high-powered psionics manifester build. #1 choice right here.
Access: PrC, whenever you can get ahold of 2nd level arcane spells. I would recommend going after the most spells per day you can.