What the heck are "Fighting Attacks"
The first big change in Serpent Lantern is that all energy-building attacks have been normalized. All of them deal the same damage and gain the same energy-per-second. Damage across the board was increased by a moderate amount, while energy gain was reduced greatly. As a concession, ranking up the energy builders now increases energy gain, but it also requires Rank 3 to get to where it currently is on the Live servers.
While playtesting the Serpent Lantern, I used my STR/PRE fire/invulnerability tank. My energy building felt very weak compared to the Live version of my character. My teammate for the arc was playing an END/REC Gigabolt spammer, who was not affected enough to really hurt his strategy. My invul tank struggled with energy issues, despite having over 200 stat points invested in energy-management stats (END, REC, and INT).
Fortunately, the devs caved to overwhelming negative feedback and made the base energy gain be relatively similar to the current energy gain on Live, with ranks increasing it by 10% each. This hasn't hit Test yet, so be on the lookout.
I'm not trying to make it impossible to be a block tank
The changes to blocking are not universally negative, although they are viewed by the players in a similar light.
A blocking character recovers some energy while blocking attacks. The new changes alter the energy gain so that it is based on both received damage (after all reduction from blocking, defensive powers, and so on) and the character's EGO stat. The change is probably intended to encourage tanks and characters who block a lot to pick up EGO as a stat. Without statting for EGO, blocking is mostly worse than it is on Live.
Not everything was nerfed horribly -- blocking had caps added for both minimum and maximum energy gain from blocking. The minimum amount is rather high, while the maximum amount is rather low. This has the interesting side effect of massively buffing Force Sheathe to give huge amounts of energy from blocking rapid-fire attacks.
Player feedback has been entirely negative or indifferent for this change as well. Most would be happy if energy gain from blocking was calculated on the damage your character takes before all of the reduction -- since Regeneration takes the most damage (and then heals it), it is hurt the least by this change, while Invulnerability, which relies heavily on soaking damage, is hurt badly. Other players suggested merely adding an energy-return mechanic for Invul. Others cried that Personal Force Field is hurt worse (I agree).
As with the energy-building changes, the devs caved here as well, though not as much. They intend to release a role bonus for tanking characters in Protector mode, giving them a scaling energy buff from blocked attacks based on their Constitution stat. Like the energy builder changes, this hasn't gone Live yet, but I'm definitely going to be trying it out.