Stick with canon only. There are more then enough options at launch. Some of the Star League era mechs are interesting and could be fun to see or play. While they are canon I mention that because they aren't common. But I see no reason to add any non canon mechs. While I may be wrong it is probably very safe to assume that they don't fill any new roles as far as play style goes. Also I'm not picking on OP by using the 2mechs he is linked just didn't look up my own non canon ones.
The Black Heart which was linked on page 1 is a relatively fast 70ton mech (73.22kp/h) mounted with a decent range of weapons The two Light Gauss stand out the most and seem to suggest it should be in a fast moving long range support role but the various SRMs and the Er-meds would push it into a shorter range. Which makes the Light Gausses a somewhat odd choice as their minimum range is longer (3hexes instead of 2). Honestly it really reminds me of the Pillager while attempting to fill the spot already filled by the 70ton variants of the Jagermech.
Trying to recreate the Black Heart in heavymetal Pro with the armament listed on sarna. I end up with what looks like a very disappointing mech especially using IS tech. I managed to use all the tonnage and crit space (i.e. I used endo and ferro for all you nay sayers). I end up with roughly 172points of armor or 70% of the maximum armor a 70ton mech can take.
On a nity-picky note the www.sarna.net page isn't even formatted properly for it. The armament sidebar has errors, someone took the time to add the mech into www.sarna.net but didn't take the time to properly format all the little details.
The other mech linked is the Warthog. Using clan level 3 rules in heavymetal Pro I can get 100% of the max armor for a 95ton mech and 12double heatsinks for it's load out. i.e. this mech overheats like a ****, unless you are willing to strip tons of armor off of it to get the required heatsinks.
2x atm 6 6 heat each
2x LBX 20 4 heat each
(generating 20heat at this point)
4x heavy medium lasers 7 heat each (28 heat)
Total weapon heat: 48 heatsinks 12dbl for 24
On another note CSA had the Dire Wolf as did all clans which is an Omni-Mech they could just put a different load out in the omni-pods. Clans also seemed to favor bird like legs for whatever reason and didn't have very "human" forms which from the description of the Warthog it sounds distinctly humanoid and thus not very clan like. The description on sarna address this by saying it was a rediscovered Star League era design. Sounds like a weak answer. Also Star League era designs as a whole tend to have significantly better heat management then the Warthog.
Both of the mektek mechs seem to be designed with the MW4 online play in mind. They both have strong alpha strikes but lack in heatsinks badly.
TL;DR The 2 non canon examples are duplicates for already filled roles and seem to be quite obviously designed for the alpha strike shutdown nature of a large amount of MW4 online play. Keep them out of the game please.
Edit: I can like my own post.

/amused
Edited by Chinook, 17 February 2012 - 09:31 PM.