I know 3.5 system very well and I played it for ages both as a player and as a DM and I can guarantee it will not blend well with the way PS and its settings is designed. I could go down to finely explain why point by point but it would take too much time, just let me say the magic system will not blend at all.
Running an
old school D&D campaign on roll20.net there was a difficulty of most players not having access to the original basic/expert rule set. This lead me to simplifying parts of the system that required detailed knowledge/charts. One such area was magic.
In the original system there is the complicated handling of spells to level. That is to say, for example, a fifth level MU gets 2 first level spells, 2 second level spells and 1 third level spell when totally fresh for the day. When the player loads up his/her/kra's character in my online software many charts are uniquely generated for the character. One thing that is generated is
spell points. Each spell is assigned X spell points. All first level spells are assigned 1 spell point, second level spells 2 spell points, third level spells 4 spell points and so on in an exponential fashion each level. A fifth level MU in my system gets 10 spell points to be used as they wish. The spell point assignment could be modified according to their intelligence (INT) stat to provide some variance. Each time a spell is used a record is kept. When they total the number of spell points that the software assigns them for their level then they are out of spells for that day. This system could be used on any magic system that the GM has assigned spell points to the list of available spells. It would not matter what
Way is used, only if the character has the needed spell points left to cast it.
As far as classes are concerned, taking the old D&D system it would be my suggestion to only use the human stats with slight tinkering of those charts to give slight modifications for the different PS races. Kran would get strength (STR) bonus, perhaps others dexterity (DEX) and so on; much like halflings in D&D have.
My players generate their characters in cgi scripts of my creation. Those scripts then generate the D&D charts unique for each character. Most of my players have never seen a D&D basic/expert rule set. Yet with their unique charts that will change for them as they level and a list of spells and what they do they have all that they need to get up and running. Simplicity should be what is being sought in a system for PS. Many players come into my campaign having never played RPG and never having seen D&D rule sets; yet are role playing from the first session.
Who needs
graple and
climb skills when they can roll against dexterity (DEX) stat? The GM is there to add mods to the rolls so that, although the same basic roll, with mods it does not seem like it. My motto is the KISS approach (Keep it simple stupid). We are there to play not take a 1st year course in d20.
When all else fails we have a
luck roll. A 1d100. Fifty or less they get their luck. Fifty-one and greater they fail. A player found a +1 sword in a treasure a few weeks ago. They asked what type of sword it was. They were asked to roll their luck. They succeeded. Because they were a halfling it ended up being a short sword. If they had failed it would most likely have been a hard to wield two handed affair.
Eonwind has my agreement that d20 is incompatable; yet for the reason that it is too damn complicated. If this idea is going to fly it has to be simple and fast paced in my opinion.