You'll quickly find that the Evolution of Combat brought along changes to monsters, and this very noticeable to the lighthouse Dagannoth. They are now far more deadly for the unprepared, and will cut your trip very short if you go in assuming you can kill them as you used to. Momentum and Soul Split simply are NOT sufficient to offset their damage, you will NEED to use abilities to stay alive. Unlike pre-EoC, the main damage you will take are from the ranged mobs, they are also more prevalent, thus you should gear up with them in mind. Using the area for general training is ill-advised.