I have been running lots of pugs while leveling and here are some of my opinions on revised or new abilities coming to holy paladin in cataclysm which I have tried out.

Beacon of light – With beacon changed 50% duplicated healing rather than 100% it has again thrown into question the main purpose of this ability as I can no longer rely on beacon to keep a tank alive without direct intervention, it has been relegated to been used as a buffer much like other classes would use hots or reactive heals to keep a tank alive while they are doing something else.
Unlike similar buffer abilities beacon requires us to be standing still and actually healing which makes it useless in situations when I have to move or are otherwise incapacitated, while beacon may heal for much more than other abilities which fill the same niche it does not help when I am directly healing the tank other than generating extra holy power which I was already swimming in.
I found myself using beacon on myself more than the tank so I would have one less person to heal through AoE damage which means I could focus on the tank more and to make sure beacon was actually doing something productive for the mana I was spending on it.
As paladin now completely lacks automatic healing with the removal of sacred shield and the associated hot I would suggest that beacon became capable of healing targets without our direct intervention at least for a limited period such as absorbing 50% of all healing we do over 6 seconds then releasing it as a hot over the next 6 seconds.

Light of Dawn and Holy Radiance – These abilities are both highly situational and that situation is obviously not 5 man or probably even 10 man yet they both fill the same niche which leaves us with a massive hole in our toolbox, neither of these abilities even in perfect situations can even make a dent in the raw amount of aoe damage thrown around in just normal 5 man dungeons so I was back to attempting to keep everyone up with a flurry of casted heals rather than making any real decision.
Even if these abilities healed for significantly more than they do at the moment however we will still lose healing and time to stop casting and reposition ourselves which is a problem other healers simply do not have with similar abilities so we will always be slower to react to aoe damage than other healers.
Another significant handicap on these abilities is the long cooldown on both of them which means holy paladin will just be a raid healer 1/3rd of the time compared to everyone else who can devote themselves to raid healing full time.
We really need an ability capable of dealing with small scale high damage aoe like that found in 5 man dungeons or 10 man raids since we lost our tank healing dominance.

Word of Glory – There have been some situations where I have been able to keep myself alive while tanking multiple dungeon mobs or even bosses with chain word of glory because of the amount of holy power generated by tower of radiance, blessed life and chain holy shocks.
I don't find spamming holy shock to be able to cast a slightly weaker version of the same spell very fun and I can already see word of glory been extremely overpowered in PvP.

Divine Plea – Now more than ever I feel is is mandatory to use a cooldown every time I cast divine plea especially in situations with large amounts of aoe which is generally when I have to use divine plea.
I would suggest having holy power reduce the healing debuff on divine plea or for the healing debuff to be removed and for holy power to extend the duration which would make it a choice to use divine plea over other holy power consuming abilities.

Sacred Shield – I really think we need a reactive healing ability that does not require our direct attention or presence considering we are now the only healer in the game without anything like that so I do not really understand why we lost sacred shield.

I feel like the overall play style of holy has returned to how I would heal during burning crusade which was simply casting flash of light or divine light over and over onto the group to heal through any form of damage however now those 2 heals are exactly the same as the 2 heals everyone else has, while it may be viable to heal like that it is not particularly fun and I find myself getting stressed during periods of heavy aoe while still keeping the tank up much like i did when healing older heroics such as MgT before the nerfs.