I know, i know. I may have sounded harsh, but after spending close to 5-6 hours creating characters with my players, to only come at the conclusion that the whole concept of his character was ruined because he could not cast spells while in full plate... well... let's say it didn't go so well. 
Except he can cast spells whilst in armour. It's just hard and prompt to fail.
The point is, i'm not comparing it to ad&d, but it just seemed weird at the time to have a Channeling profession that could wear Full Plate even though it prevented the player to cast spells.
Uh, what? Each and any profession in RM2 could wear each and any type of armour. If you want, you can have your pure Essence spell caster develop proficiency in full plate and wear one in combat, whilst casting spell at the same time. The DP cost would be high, the ESF chances would be high, but it's possible!
Come on, you know very well what i meant... Paladins' cost for full plate is (if i remember correctly) 4 DPs per rank. Compared to other Pure and Hybrid professions (most are around 20 Dps if i'm not mistaken, again), it is clear that the paladin was meant to be able to wear it easily.
Right now, i've ruled that some specialized class (such as Paladins and Clerics and so on) could get their armor blessed, thus bypassing the metal limitation, but other professions would require Transcend Armor skill to cast while wearing armor.
Your game, your rules but IMO this is an horrible way to manage the situation. In a nutshell, what you did equals to "What? Howcome Fighters don't have weapon skills? OK, I rule that some specialized classes (such as the Fighter) automatically gain two free weapon ranks each level whilst other professions would require buying the weapon ranks." Why make a special rule that only applies to some professions whilst the system already take the situation you described into account (by the way of the Transcend Armor skill). So, yes, Paladins are "required" to put ranks into the Transcend Armor skill to conform to the "Full Plate Paladin" image... the way a Fighter is "required" to put ranks in a weapon skills to conform to the "Fighter knows to fight" image, or a spell user is "required" to put ranks into his spell lists to be able to cast spells. In other words, yes, a Paladin can cast spells (with no ESF) whilst in armour, he just doesn't automatically gain proficiency in doing so... no more than a Fighter automatically gains proficiency in weapons, nor a spellcaster automatically gains proficiency in spell casting. The three of them have to learn (i.e. put DPs) in the appropriate skill.
Well, as a limitation, as providence13 mentioned, if they ever get another armor, or have to repair it, they'll have to have it blessed again by their church. Which i feel is fair, considering there won't always be a church of their order nearby, and that Paladins and Clerics are specifically trained to channel spell in armor.
I've also left them the option to put ranks in Transcend Armor if they wanted to.
Also, your example is not completely accurate, in that a fighter has only to spend ranks in it's weapon to be able to use it, whereas the paladin has to buy ranks in it's spell list, and then again in Transcend Armor just to be able to use it.
It's as if i'm requiring every fighter to not only spend ranks in it's weapon skills, but also the material it's made of. "Oh! Using a metal sword? Hope you have that Transcend Metal skill, boy..." I'm exaggerating of course, but surely you can understand what i meant.
