Personally don't like the current Beacon of Light. Here are some of the complex problems that arise from the new version.
1* The beacon target essentially is healed randomly, you cannot control your healing output on the Beacon'd target because friendly targets take damage at different times. So the real only advantage is when you spam heals.
2* Dispel-able, making it mostly useless for PVP.
3* Doesn't work on overheals, this is connect to the first point. So not only do the targets have to both be taking damage at the same points in time, but both have to be damage for the Beacon to be fully effective.
4* Its 1.5 second cast time downgrades its use even further in PVP, connected to point 2.
5* Its high mana cost further degrades its use in most situations, a Paladin should have the option to effective switch the Beacon from player to player without feeling "to" disadvantaged while doing so.
Beacon of Light instead of helping our viability as a healer in PVE or PVP just mimics what we already do. So instead of improving our healing it is effectively multiplying and doubling what minor or ineffective healing we do (and doubling it randomly, since targets take damage at different points). It is an interesting idea and a good concept, but like all of our talents in all our trees currently (and the new base skills we are not receiving yet need) isn't fully developed into what it should be.
There are only a few situations currently in PVE where Beacon of Light really stands out, both are similar, firstly is Illidan Phase 2 which can effectively be done by two spamming Paladins with this ability. Secondly and the most effective is Brutallus which effective cuts the Paladins needed in half because all Holy Paladins are doing on Brut is spamming heals without really effectively looking at health bars. And even then, you are spamming one target with Heals, yet any over heals are not repeated to the Beacon'd tank, and if you heal your target'd tank the Beacon tank may very well be fully healed already.
(made the last sentence notable because it brings out all the faults that Beacon of Light comes with)