I think it's abundantly clear that the Magus is designed with 2 major goals in mind.
1) It has to be designed on a 3/4 BAB bard equivalent chassis. While a full BAB paladin progression arcane knight class might be an appropriate addition for a future class it's pretty clear that within the minds of the designers Full BAB d10 HD Bard progression is not going to happen with this class. Yes, clerics and druids are poorly balanced but they shouldn't necessarily be the yardstick by which new classes are designed.
2)It cannot be better at a core class(fighter,cleric,wizard, rogue) competency in their central schtick (damage dealing, healing/buffing, control, skill monkey) except on a limited duration basis. It's a hybrid not a specialist and as such pays a premium for it's increased versatility and utility.
Given those 2 design goals how can the 3/4 BAB progression Bard Casting Martial character find a unique schtick and be useful in a party?
Borrowing what has already been designed it seems clear that there are several key features that Paizo wants to highlight. Spellstrike, Spell Combat and Arcana are the key features of this class currently and should be retained (but heavily modified). Additionally as single weapon specialists it's clear that in their given field they should be fighter equivalents.
Design Element 1- Spellstrike: It's clear that this ability is poorly worded currently. I think the primary goal is to allow a Magus to spam touch spells in conjunction with melee attacks. Unfortunately this is currently limited to spamming shocking grasp.
Solution 1 - People already seem to be assuming that this is in effect imbuing the weapon with a spell. Go ahead and make it equivalent to imbue rather than a held spell. That way the Magus can hold a touch spell charged in his weapon and release it as needed while still being able to cast other needed spells. If unlimited duration is too much then limit it to 10/min a level.
Solution 2 - Arcane casters generally benefit more from having access to status effects, debuffs, and control effects. Additional touch spells that allow higher level magus characters to spam status effects (stun, shaken, fear, slow, etc) and other debuffs (touch of idiocy, enervation, etc) would go a long way towards helping the Magus live up to his potential.
Design Element 2- Spell Combat: If the core concept is to allow two-weapon combat where spell casting is equivalent to a offhand weapon go ahead and make it so.
Solution - The off hand casting hand is equal to a light weapon, spell combat should be equivalent to having TWF feat. Thus the penalty to the base attack should be -2 to the primary hand. If the caster chooses to cast defensively (not always required) he takes a -2 penalty to the concentration check (this penalty reduces over time). As a committed melee character he needs combat casting as a bonus feat either given at level 1 or whenever spell combat shows up.
Design Element - single handed weapon use: Let's face it we are aiming for a elven F/MU like Melf and the 2e bladesinger with this class.
Problem- Single handed weapon usage generally blows. 3/4 single handed weapon blows harder. If we are committed to limiting the Magus to a single handed weapon there should be ways of reliably boosting the Magus base DPR to acceptable levels even if it's a limited duration effect.
Solution part 1- These guys are weapon specialists, allow them to function as fighter of equivalent level when purchasing feats for one weapon (single handed like a long sword). That way you generally will be seeing WF: Long Sword, GWF: Long Sword, WS: Long Sword, GWS: Long Sword on any given Magus.
Solution part 2- Even moreso than the duelist these guys should be the lightly armored striker. Give them precision damage (+1 at 1st, +1 for every 2 to 3 levels past that), Give them a defense bonus equivalent to their intelligence. Combined with two handed grip when not using spell combat and this should get the magus closer to a martial character in terms of DPR.
Solution part 3- Considering making a magus only arcane variant of Divine Power. The ability to boost BAB to full progression even if it's only for limited duration would allow the Magus to buff to the point where he can hit really hard but that would come at the cost of limited duration. So just like the Paladin can outshine the fighter in a limited number of scenarios this would allow a mid-tier magus to boost his DPR into the stratosphere for a limited duration.
Magus Arcana - While I haven't looked to much at these, it seems that in generally they should offer similar utility to metamagic due to the magus largely being restricted from using metamagic like quicken (to expensive) or metamagic wands (no free hands).