Tabletop RPG Mechanics I Want

I've been thinking about system stuff recently, having been reading through d20 rules and several variants thereof for the first time. I was trying to think about what I like in my systems. This is the start of my brainstorming. This is a snapeshot of my current thinking...I'msure I'll have changed my tastes within a few months.
• Simple set of stats, 4-6
• No more than two dice types: d10 and d6 are my preferred
• No more than 30 skills; a few have specializations (Craft, Science, Knowledge, etc)
• Point based character creation
• Stats affect the resolution about 1/3, skill levels affect the roll about 2/3
• Target number is up (i.e. roll X die + stat + skill against target number)
• Synergy bonuses for certain skills
• Point totals over levels to measure general character power. Characters with the same number of points will feel balanced relative to each other
• Initiative is rolled once and then stays that way unless other circumstances intervene
• Characters can learn specific combat styles which allow them to learn maneuvers, giving them some flavor and strategic choices
• There are a set of combat elements which can be easily put together to create maneuvers and see how balanced they are.
• One track for measuring damage (i.e. no Stun and Body as separate numbers) but when a character takes significant damage they may have to test for stun, shock or death
• Multiple actions possible in a round
• Damage and weapons have enough variance that they feel different, i.e. a broad range of damage numbers, but not so much that some weapons are useless
• Characters can buy advantages/talents/abilities and flaws/drawbacks/etc
• Advantages feel balanced • Complex combats can be done in under an hour
• Magic system has structure but players can modify the effects
• Called shots and criticals can be done • System can easily model stunts and cinematic actions
• Magic is quick and balanced to other combat abilities

Here’s the thing I’m grinding on in my thinking: Active Defense versus Target Number. In a target number system, the attacker rolls to hit the defense number of the target (examples: Champions, Hero System, d20). The target can buy effects or take maneuvers to raise their target number. In an active defense system, the attacker and defender contest rolls (examples: Unisystem, Storyteller, Gurps). In this case multiple defenses are restricted somewhat, though penalties, dice pool splitting or choice of defenses respectively. The target number system has the advantage of speed. The active defense has the advantage of participation. I’m not sure which I like better.

Let me put this out there too, in terms of defenses and defense rolls.

Gurps allows an active defense roll, but you get one parry, one block (if you have a shield) and unlimited dodges. You can only do one defense per attack (unless you do an all-out defense maneuver). Typically your parry and blcok scores are higher than dodge, so as you take more defenses in a round your chances get lower. Storyteller, old system, has the dice pool split, so you have to declare the number of actions when you go. Since each additional action takes dice off, your defense number goes lower. [As a side note, it is my understanding that a characters dodge number is fixed in new WoD]. Likewise Rolemaster has you divide your defense value among the various attackers. Unisystem has has multiple actions-- you get a free defense and attack, all actions after that reduce your defense roll. Also, I think classic Unisystem (non-cinematic) doesn't allow defense rolls against ranged attacks unless you take your full action to dodge. Champions and d20 don't have an effect for taking multiple defenses, since attackers are rolling against a target number. If believe both have a bonus added for multiple attackers (i.e. a ganging up rule). Also, I believe the Dodge feat allows you to choose to apply a bonus to your "AC" of +1 against everyone or +2 against a specific attacker. I can't remember how Shadowrun, Cyberpunk, L5R, etc handle this.

I guess my question is: *If active defense, should you have a reduction in your defense attempts as you take more. Should there be a minimum to this roll? Should those actions count against your normal allotment of actions in a round? *If target number, what's the most satisfying way to handle defneding against multiple attacks-- a bonus to the attackers roll or something else? Should you be able to take actions to bump your target number, and if so how many and how do they count against your regular actions?

Sidenote: I was thinking about the d20 system of target numbers. Mutants and Masterminds has an option where instead of trying to hit a target's Base Defense+Dx Bonus+Modifiers+10, you substitute a d20 roll made by the defender instead of that +10. This would give the defender some participation in the action.