I never said anything about those talents or powers being "inaccessible." In this system there's pretty much no such thing as "inaccessible" as it all boils down to "how much XP are you willing to pay to get it?" whether it be buying additional specializations to access certain talents, including multiple instances of a specific talent, such as Toughened, Durable, Side Step, Dodge, Hard-Headed, Parry, or Reflect.
The fact that under the current set-up, the Shien Expert pretty much has to take abilities that are not an inherent part of the Shien Expert talent tree is part of the issue, unless the player has an overly generous GM that only has bad guys make ranged attacks from Long or Extreme Range most of the time. None of the other LS Form specs are required to take such abilities, be they talents or Force powers, that are outside their specialization in order to improve their chances of having Improved Parry work, as their set-up includes such things already as I detailed earlier in the thread.
But let's take a look at some of the other specializations, ones that having nothing to do with lightsabers. All of the following examples were randomly chosen simply by flipping open the book and looking at whatever specialization I landed upon.
An Aggressor doesn't have to dip into other specializations or Force powers in order to be a terrifying presence in combat; the spec offers multiple ranks of Fearsome and Intimidating as well as offering Coercion as a bonus career skill.
An Advisor doesn't have to dip into other specializations to be good at dealing with people, as Charm, Deception, and Negotiation are all career skills, and it offers ranks in Smooth Talker, Plausible Deniability, Kill with Kindness, and Nobody's Fool to enable them to be masters of social encounters, and can do so without ever so much as looking at Influence or even Sense for the emotion/thought reading.
A Peacekeeper doesn't have to dip into other specializations to be good at leadership (has it as a skill and has talents that bolster Leadership checks), and can use Field Commander just fine without having to buy anything that's not already included in the specialization, and Battle Meditation certainly isn't a requirement to do their thing, and may in fact be deemed a waste of XP that could be better spent elsewhere.
A Healer doesn't have to dip into other specs to be good at healing people, with plenty of ranks of Physician and Surgeon and having Medicine as a bonus career skilll; having the Heal/Harm power certainly helps, but they can get by just fine without it. Dipping into Protector or even AoR's Medic certainly helps their healing prowess (particuarly for the Stimpack Specialization talents), but neither of them are required to allow the Healer to do their thing, namely healing people.
Niman Disciple comes close in that it requires the Move power for two of it's major talents (Draw Closer and Force Assault), but the odds of a PC with this spec not taking Move at all are pretty darn slim. And if they don't want the talents, they can be very easily side-stepped. And even without those talents, as written it's still a pretty effective combat spec that even offers an increase to Force Rating while boosting up your ranks in Parry and Reflect (3 ranks of each), making it a very likely secondary spec for most 'saber-monkey characters in addition to adding ranks of Defensive Training (handy if you've got Improved Parry) as well as Center of Being and Improved Center of Being. Nothing to help against ranged attacks, but since there's no Improved Reflect outside of Shien Expert, not a big deal, and it does fit with the film canon that Niman's not really that great in prolonged combat against multiple foes (if one accepts the notion put forth that the majority of Jedi that died at Geonosis were Niman practitioners).